| a competitive labeling method for the determination of the chemical properties of solitary functional groups in proteins. | the properties of the functional groups in a protein can be used as built-in-probes of the structure of the protein. we have developed a general procedure whereby the ionization constant and chemical reactivity of solitary functional groups in proteins may be determined. the method may be applied to the side chain of histidine, tyrosine, lysine, and cysteine, as well as to the amino terminus of the protein. the method, which is an extension of the competitive labeling technique using 3h- and 14c ... | 1975 | 42 |
| production, purification, and characterization of an extracellular chitosanase from streptomyces. | the synthesis by streptomyces sp. no. 6 of an extracellular chitosanase was induced by glucosamine. the enzyme was purified to homogeneity by sephadex g-100, carboxymethyl-cellulose, and diethylaminoethyl-cellulose chromatography. the purified enzyme hydrolyzed chitosan (the beta-1,4-linked polymer of glucosamine) but not chitin nor carboxymethyl-cellulose. the only products of the hydrolysis detectable by paper chromatography were di- and triglucosamine. sephadex g-100 chromatography and sodium ... | 1975 | 371 |
| structural studies of two ovalbumin glycopeptides in relation to the endo-beta-n-acetylglucosaminidase specificity. | heterogeneities of the two ovalbumin glycopeptides, (man)5(glcnac)2asn and (man)6(glcnac)2asn, were revealed by borate paper electrophoresis of oligosaccharide alcohols obtained from the glycopeptides by endo-beta-n-acetylglucosaminidase h digestion and nab3h4 reduction. the structures of the major components of the oligosaccharides were determined by the combination of methylation analysis, acetolysis, and alpha-mannosidase digestion. based on the results, the whole structures of the major comp ... | 1975 | 389 |
| proteolytic enzymes of the k-1 strain of streptomyces griseus obtained from a commercial preparation (pronase). purification and characterization of the carboxypeptidase. | we described earlier the facilitated purifications of the trypsin and aminopeptidase components present in pronase (vosbeck, k. d., chow, k. -f., and awad, w. m., jr. (1973) j. biol. chem. 248, 6029-6034). a partially resolved protein mixture left over after one of the steps in that procedure was passed through a sephadex g-75 column. by this means, a component with carboxypeptidase activity was separated from associated serine endopeptidases. further purification of this exopeptidase to apparen ... | 1976 | 399 |
| a comparison of the substrate specificities of endo-beta-n-acetylglucosaminidases from streptomyces griseus and diplococcus pneumoniae. | | 1975 | 1016 |
| purine nucleotide pyrophosphotransferase from streptomyces morookaensis, capable of synthesizing pppapp and pppgpp. | purine nucleotide pyrophosphotransferase was purified to apparent homogeneity from a culture filtrate of streptomyces morookaensis. it is a monomeric protein with a molecular weight of 24 000-25 000, and its isoelectric point is 6.9. the enzyme synthesizes purine nucleoside 5'-phosphate (mono, di, or tri) 3'-diphosphates such as pppapp, ppapp, papp, pppgpp, ppgpp and pppipp by transferring a pyrophosphoryl group from the 5'-position of atp, datp and ppapp to the 3'-position of purine nucleotides ... | 1975 | 1088 |
| l-alphas, 5s-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid (nsc-163501): a new amino acid antibiotic with the properties of an antagonist of l-glutamine. | l-alphas,5s-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid (nsc-163501), an antibiotic elaborated by streptomyces sviceus, has been shown to be a powerful inhibitor of many mammalian and bacterial reactions involving the transfer of nitrogen from the gamma-carboxamide of l-glutamine. thus, the utilization of l-glutamine for the synthesis of carbamyl phosphate, l-asparagine, guanosine-5'-monophosphate, cytidine-5'-triphosphate, n-formylglycinamidine ribonucleotide, nad, glucosamine-6-pho ... | 1975 | 1147 |
| control of differentiation in streptomycetes: involvement of extrachromosomal deoxyribonucleic acid and glucose repression in aerial mycelia development. | when streptomyces alboniger spores were grown in hickey-tresner broth containing 5 mum ethidium bromide, a high frequency of permanently cured aerial mycelia-negative (am-) colonies was recovered. the appearance an am- colonies was time dependent: a very low frequency (0.3%) at zero time, a maximum (9 to 21%) after 2 to 5 days of growth, and a decline again to low frequencies later in the growth cycle. on agar, cured am- colonies of s. alboniger still produced puromycin. the development of aeria ... | 1976 | 1384 |
| factors causing lysis of an actinomyces rimosus culture, the producer of the antibiotic, oxytetracycline. | the lysis of actinomyces rimosus producing oxytetracycline during its mass growth can be caused by two factors which were separated by differential centrifugation. the first factor is phage particles of a temperate phage produced by the culture; they are incapable of growth but may induce the lysis. the phage particles treated with low ph and a temperature of 70 degrees c lose the lytic activity. the second factor is a lytic enzyme produced under the control of the temperate phage during its ind ... | 1975 | 1634 |
| the effect of microbial mycolytic agents on trichophyton rubrum. | chitinolytic microorganisms isolated from forest soil and from healthy gypsy moth larvae (porthetria dispar (l.) were screened for their ability to lyse trichophyton rubrum mycelia. a few of these isolates were mycolytic on both autoclaved and on actively growing, intact, t. rubrum mycelia. supernatants from these isolates, utilizing live t. rubrum as the sole carbon source, showed the same mycolytic ability. assays of the supernatants for enzymatic activity revealed exocellular, stable enzymes ... | 1975 | 1677 |
| hydrolysis of insoluble collagen of bull bones by streptomyces griseus crystalline protease. | hydrolysis of collagen was studied in the bull bone tissues by the str. griseus crystalline protease. the amount of collagen hydrolyzed by it composed 6.6% and 16% after 4-hour and 6-hour hydrolysis, respectively. when the enzyme:substrate ratio is 1:50 hydrolysis proceeds most intensively; with a decrease in the ratio up to 1:1000 the average amount of peptides increase from 2.6 up to 4 amino acidic residua, respectively. under conditions of denaturated collagen hydrolysis the content of hydrox ... | 1975 | 1884 |
| effect of the phosphorus concentration on novobiocin formation by the producer act. spheroides. | according to the literature data biosynthesis of novobiocin by act. spheroides unlike other antibiotics does not practically depend on the phosphorus levels in the medium. in the present paper it is shown that production of novobiocin in natural media is sensitive to the concentration of mineral phosphorus in the medium. the optimal concentration of phosphorus for biosynthesis of novobiocin is almost within the same ranges as that for biosynthesis of streptomycin, tetracyclines and oleandomycin. | 1975 | 2094 |
| purification and properties of the thermostable acid protease of penicillium duponti. | an acid protease produced by the thermophilic fungus penicillium duponti k 1014 has been purified by consecutive ion-exchange and gel permeation chromatography, and crystallized from aqueous acetone solution. the purified endopeptidase gave a symmetrical schlieren peak by sedimentation velocity, and was found to be homogeneous upon disc gel electrophoresis at ph 9.5. the enzyme was most active at ph 2.5 against milk casein and showed high thermostability. an isoelectric point of 3.81 was found b ... | 1976 | 2287 |
| enzyme induction in streptomyces hydrogenans. v. characterization of testosterone-17 beta-dehydrogenase and its induction by steroids. | testosterone 17beta-dehydrogenase can be enriched from streptomyces hydrogenans. the enzyme dehydrogenizes testosterone with km=13mum and estradiol-17beta with km=21mum to the corresponding 17-ketoderivatives. nad forms nadh with km=125mum. the enzyme is strongly inhibited by androstandione and 17alpha-methyltestosterone. the ki for 17alpha-methyltestosterone is 18mum. the enzyme activity increases with increasing ph up to alkali-mediated denaturation at about ph 10. the optimum temperature is a ... | 1975 | 2532 |
| affinity chromatography of trypsin and related enzymes. i. preparation and characteristics of an affinity adsorbent containing tryptic peptides from protamine as ligands. | an absorbent for the affinity chromatography of trypsin ec 3.4.21.4 (ap sepharose) was prepared. the ligand was a mixture of oligopeptides (mainly di- and tripeptides) containing l-arginine as carboxyl termini, and was obtained from a tryptic digest of protamine. trypsin was absorbed at relatively low ph (7-4), but was not absorbed at the optimum ph of catalysis (8.2). this was clearly explained on the basis of the ph dependence of the interaction of trypsin with its products. inactivated trypsi ... | 1975 | 2582 |
| non-specific acetyl-coa carboxylase and methylmalonyl-coa carboxyltransferase in streptomyces noursei var. polifungini. | 1. acetyl-coa carboxylase (ec 6.4.1.2) and methylmalonyl-coa carboxyltransferase (ec 2.1.3.1) have been isolated from mycelia of streptomyces noursei var. polifungini, and purified about 50-fold. 2. both enzymes carboxylate acetyl-coa and propionyl-coa; the respective km values are 1.1 and 1.6 mm with acetyl-coa carboxylase and 2.5 and 1.25 mm with carboxyltransferase. 3. the activities of both enzymes are inhibited by free fatty acids. almost total inhibition of methylmalonyl-coa carboxyltransf ... | 1975 | 3079 |
| an endogalactosaminidase from streptomyces griseus. | an endogalactosaminidase has been purified 34-fold from the culture filtrate of streptomyces griseus. this enzyme cleaves galn-galn linkages in oligogalactosaminoglycan, a galactosamine-rich oligosaccharide isolated from the culture filtrate of a neurospora mutant. since some or all of the galn-galn bonds in this molecule link positions 1 and 4, and are in the alpha-configuration, we are probably dealing with an endo-alpha-(1 leads to 4)-galactosaminidase, bu this characterization is only tentat ... | 1975 | 3271 |
| inducible accumulation of alpha-ketoglutaric acid in cultures of streptomyces hygroscopicus ja 6599 producing a macrolide antibiotic. | the excessive production of pyruvic and 2-oxoglutaric acid by s. hygroscopicus ja 6599 grown on a medium rich in complex carbon and nitrogen sources was studied. towards the end of the first day of batch cultivation a maximum level of both keto acids in the medium was observed. by diluting the complete culture with water at 22nd hour, however, a further increase in 2-oxoglutarate concentration was induced and the antibiotic production was slightly stimulated. in diluted cultures the oxygen satur ... | 1975 | 3895 |
| biosynthesis of chloramphenicol in streptomyces sp. 3022a. identification of p-amino-l-phenylalanine as a product from the action of arylamine synthetase on chorismic acid. | products obtained from the action of arylamine synthetase on g-14cchorismic acid were fractionated by gel filtration and ion exchange column chromatography to yield a partially purified radioactive component with an arylamine function. from its ultraviolet absorption spectrum and thin-layer chromatographic behaviour the product was considered to be p-aminophenylalanine and the identification was confirmed by co-crystallization with an authentic specimen. specific deamination of the product with ... | 1976 | 4210 |
| antimycin a fermentation. ii. fermentation in aerated-agitated fermenters. | fermentation characteristics, previously studied in shake flasks, were reproduced in aerated-agitated fermenters, using three strains of streptomyces sp. which had been selected for their high antimycin a productivity in shake flasks. fermentation in fermenters was run in three stages. the medium consisted of soy flour, glucose, ammonium sulfate and calcium carbonate; initial ph was 7.2 approximately 7.5, and temperature 25 degrees c. the course of fermentation was then modified to encourage max ... | 1976 | 4419 |
| nutritionally defined conditions for germination of streptomyces viridochromogenes spores. | spores of streptomyces viridochromogenes were removed from the surface of solid media with glass beads and suspended in a buffer-detergent solution. addition of yeast extract and glucose resulted in rapid loss of refractility of the spores. appearance of germ tubes followed. germination was accompanied by a decrease in the optical density (od) of the suspension. the od decrease was used as an assay for germination. a defined germination medium (dgm) comprised of l-alanine, l-glutamic acid, adeno ... | 1976 | 4421 |
| heat activation of streptomyces viridochromogenes spores. | the lag period preceding germination of streptomyces viridochromogenes spores during incubation in a defined germination medium was completely eliminated by a gentle heat shock. the rate of germination was not affected. the optimum ph for activation extended from 6.0 to 9.6. the time of heating required for maximum activation was 1 min at 60 c, 2 to 5 min at 55 c, 20 min at 50 c, and 40 to 50 min at 45 c. activated spores had the same temperature and ph optima and nutritional requirements for ge ... | 1976 | 4424 |
| studies on phospholipases from streptomyces. iii. purification and properties of streptomyces hachijoensis phospholipase c. | 1. phospholipase c ec 3.1.4.3 found in the growth medium of streptomyces hachijoensis was purified about sixty-fold by dialysis and column chromatography on sephadex g-50. 2. the active fraction was separated by isoelectric focusing into two fractions, phospholipase c-i (pi 6.0) and phospholipase c-ii (pi 5.6). 3. both purified phospholipases c were homogeneous by immunodiffusion and were not differentiated as regards antigencity. 4. phospholipase c-i had maximal activity at ph 8.0 and the optim ... | 1975 | 5411 |
| properties of delta5-3beta-hydroxysteroid oxidoreductase isolated from streptomyces griseocarneus. | delta5-3beta-hydroxysteroid oxidoreductase was extracted in magnesium-containing tris buffer from sonicated streptomyces griseocarneus cells. the enzyme was partially purified (150 x) by ion exchange chromatography and gel filtration following (nh4)2so4 fractionation. upon gel filtration on sephadex g-75 to g-200, the greatest part of the activity gave a peak in the fractionation range. the enzyme obtained from the gel yielded small enzyme molecules on repeated chromatography. a molecular weight ... | 1975 | 5856 |
| a rapid assay for the binding of actinomycin to dna. | | 1976 | 5913 |
| criteria for evaluating calcium carbonate from the point of view of chlortetracycline biosynthesis. | calcium carbonate is added to fermentation media in biosynthesis of tetracyclines for providing definite ph values and binding tetracycline into insoluble complexes. seven different samples were studied with respect to their physical properties, such as the microscopic size of the particles, their form, capacity for agglomeration, specific volume, rate of the particle precipitation and chemical properties, such as purity, buffer capacity, effect on the medium ph before and after sterilization. t ... | 1976 | 5942 |
| regulation of tetracycline biosynthesis by controlling the growth of the producer. | regulation of the rate growth of act. aureofaciens in batch fermentation by maintaining the concentrations of phosphorus, ammonium nitrogen, glucose and ph values at the levels favourable for intensive growth at the beginning of the process and after accumulation of the biomass at the levels optimal for retarded growth of the organism resulted in significant prolongation of the period of intensive antibiotic production, i.e. intensification of the fermentation process. microscopic investigation ... | 1976 | 5948 |
| study of the biosynthesis of a carbohydrate fragment of rubomycin. | when the rubomycin-producing organism was grown in the presence of an evenly labeled c14-glucose and various non-labeled carbon sources, the carbohydrate part of the antibiotic also became evently labeled. the activity of i carbon atom of rubomycin sugar grown against the background of non-labeled glycerol was almost 3 times higher than the respective value of the aglycone activity. c14-acetate, c14-propionate, c14-methionine and daunosamine were not incorporated. the data are indicative of the ... | 1976 | 5949 |
| isolation and several properties of streptomyces griseus carboxypeptidase. | enzymatic and physico-chemical properties of homogenous preparation of carboxypeptidase from streptomyces griseus are studied. ph-optimum is found to be 7.9 and 8.2 under the hydrolysis of cbs-gly-leu and hyppuryl-arg respectively, temperature optimum --60 degrees c. the enzyme splits more efficiently basic amino acids and leucine from n-terminal-protected dipeptides. str. griseus carboxypeptidase is activated by reducting agents (nacn, cisteine, ascorbic acid), it is inhibited by kmno4 and it d ... | 1976 | 6077 |
| identification and preparation of damavaricins, biologically active precursors of streptovaricins. | | 1976 | 6413 |
| purification of several bacteriolytic enzymes by affinity chromatography on lysozyme-lysate of micrococcus lysodeikticus cell wall coupled with sepharose. | using lysozyme-lysate of micrococcus lysodeikticus cell wall coupled with sepharose, several bacteriolytic enzymes were purified from crude preparations of animal and microbial origin. quail egg-white, human milk and salivary lysozymes ec 3.2.1.17 were adsorbed onto the adsorbent at ph 5-7 and eluted with 2m nacl at ph 10. by means of these treatments, lysozymes were purified 20-250 fold with activity recoveries of 60-80%, and the quail lysozyme thus purified was shown to be discelectrophoretica ... | 1975 | 6436 |
| studies on phospholipases from streptomyces. ii. purification and properties of streptomyces hachijoensis phospholipase d. | 1. phospholipase d ec 3.1.4.4 from streptomyces hachijoensis was purified about 570-fold by column chromatography on deae-cellulose and sephadex g-50 followed by isoelectric focusing. 2. the purified preparation was found to be homogeneous both by immunodiffusion and polyacrylamide disc gel electrophoresis. 3. the isoelectric point was found to be around ph 8.6 and the molecular weight was about 16,000. 4. the enzyme has maximal activity at ph 7.5 at 37 degrees. the optimal temperature is around ... | 1975 | 6440 |
| cholesterol breakdown by enzyme preparations extracted from streptomyces lavendulae. | cholesterol was decomposed by 75-90% during two hours by enzyme preparations from the disintegrated mycelium of streptomyces lavendulae. the effect of concentrations of cholesterol and protein on the decomposition of cholesterol by the enzyme was studied; the higher the content of protein in a sample, the more rapidly cholesterol is decomposed; the rate of cholesterol decomposition increases with a decrease of its concentration. the optimum ph is 7.5-9.0. after dialysis and lyophilization, the a ... | 1976 | 6861 |
| effect of different ph values on the medium on the synthesis of antibiotics in the joint cultivation of actinomyces levoris with yeasts. | changes in the ph level of the fermentation medium used for preliminary cultivation of c. tropicalis were studied with respect to its initial aciditv or alkalinitv. when c. tropicalis was grown on the medium used for levorin fermentation with ph 5.1--10.3, the yeast changed it in 24 hours to the level of 6.2--7.9. as dependent on the initial ph values for cultivation of c. trophicalis, production of levorin on subsequent inoculation of act. levoris changed. the antibiotic activity increased and ... | 1976 | 7994 |
| structure and fluctuation of a streptomyces subtilisin inhibitor. | the kinetics of the hydrogen-deuterium exchange reaction in a subtilisin inhibitor from streptomyces albogriseolus has been examined by infrared absorption measurement in aqueous solutions at various ph values and temperatures. in the analysis of each piece of kinetic data, it was assumed that the total 104 peptide hydrogen atoms are classified into three kinetic classes a, b1, and b2, and that the sizes of these classes are 72, 15, and 17, respectively at every ph and at every temperature exami ... | 1976 | 8098 |
| influences of soil acidity on streptomyces populations inhabiting forest soils. | the streptomyces populations inhabiting five acidic forest soils were examined. it was found that lowering the ph of a medium selective for streptomycetes (starch-casein agar) to the ph of the particular soil horizon being plated influenced both the total numbers and types of streptomycetes that were isolated from the soils examined in this study. on the acidified medium both the numbers of streptomycetes and the percentage of total bacteria on the plates represented by streptomycetes increased ... | 1976 | 10835 |
| chemistry of the ansamycin antibiotics. | | 1976 | 11155 |
| dependence of erythromycin biosynthesis on the active acidity of the medium. | dependence of erythromycin biosynthesis on the medium active acidity was studied by the following methods: by changing ph of the initial medium, by changing the concentration of the medium components determining the active acidity of the culture, by using buffer mixtures by automatic control of ph. it was found that ph of the initial medium within 5.7-8.1 had no effect on the culture growth. biosynthesis of erythromycin markedly decreased at ph 6.3 or lower. the values of ph within 6.6-7.5 (opti ... | 1976 | 11737 |
| inactivation of streptomyces subtilisin inhibitory by chemical modifications. | 1. the inhibitory activity of an alkaline protease inhibitor, (streptomyces subtilisin inhibitor) towards subtilisin is found to decrease by photooxidation sensitized by methylene blue with a clear ph dependence, the midpoint of which is about 6.0. 2. amino acid analyses of photooxidized streptomyces subtilisin inhibitor indicate that one of the two histidyl residues and the three methionyl residues are destroyed, concomittant with the loss of inhibitory activity. 3. in accordance with this obse ... | 1976 | 11822 |
| an unusual fluorescence spectrum of a protein proteinase inhibitor, streptomyces subtilisin inhibitor. | streptomyces subtilisin inhibitor, a dimeric protein proteinase inhibitor isolated in crystalline form by murae et al. in 1972, contains three tyrosine and one tryptophan residues per monomer unit and has unusual fluorescence properties. when excited at 280 nm, it shows a characteristic fluorescence spectrum having a peak at 307 nm and a shoulder near 340 nm, a feature which has been recognized only for a very few cases in proteins containing both tryosine and tryptophan residues. when excited a ... | 1976 | 11830 |
| comparative studies on cholesterol oxidases from different sources. | 1. comparison of the characteristics of cholesterol oxidases from different sources was made by a new polarographic method for measurement of the oxygen-consumption rate. 2. a ph optimum of 7.0 was observed for cholesterol oxidases isolated from nocardia and brevibacterium, ph 5.0 for the enzyme from schizophyllum and ph 7.5 for the enzyme from streptomyces. 3. in the system used in the present study, ca2+ and mg2+ had no effect on these enzyme activities. on the other hand, the schizophyllum en ... | 1976 | 11914 |
| inhibition of human plasma renin activity by pepstatin. | pepstatin, a pentapeptide isolated from streptomyces, is a powerful inhibitor of several acid proteases. its ability to inhibit the renin-angiotensinogen reaction was studied in vitro, in various human plasma. a 50% inhibition of plasma renin activity was obtained with 10(-6)m pepstatin at ph 5.7 and 10(-5)m at ph 7.4. the inhibition of plasma renin activity by pepstatin was studied in hypertensive patients with various plasma renin levels. the inhibitory effect could be demonstrated in patients ... | 1976 | 12191 |
| rhodnius prolixus and its symbiotic actinomycete: a microbiological, physiological and behavioural study. | | 1976 | 12514 |
| measurement of growth rates of streptomycetes: comparison of turbidimetric and gravimetric techniques. | | 1977 | 13146 |
| antibiotics produced by streptomyces olivaceus 142. i. characterization of the fpg mutant and conditions of production of antibiotic wr 142-fpg. | by treating the streptomyces olivaceus 142 strain simultaneously with ethyleneimine and uv radiation, the fpg mutant was isolated, which was characterized by the fact that in submerged cultures it produces a cytotoxic substance for fibroblasts and tumor cells and inhibits growth of pathogenic fungi. the mutant differs from other strains not only in having a different spectrum of antimicrobial activity, but also by taxonomic properties such as color of the aerial mycelium, liquefaction of gelatin ... | 1976 | 13763 |
| the fermentative production of oxytetracycline on industrial by-products by streptomyces rimosus 12907. | three strains of streptomyces rimosus were grown on four different media. the one suitable for the production of oxytetracycline by streptomyces rimosus 12907 was modified by black strap molasses, fodder yeast (40% total protein) and rice bran. the volume of the fermentation medium was sealed up in a 1200-litre fermentor aerated with sterile air obtained from a system used in the purification of air. 850 g crude oxytetracycline was obtained when the fermented medium (700 litres) was extracted wi ... | 1977 | 14061 |
| effect of streptovirudin on parainfluenza 3 virus multiplication. | streptovirudin (sv) in a concentration of 100 microng/ml reduced the multiplication of parainfluenza 3 virus by about 3.5 log units. when uninfected wish cells were treated for 2 and 12 hours with 100 mug/ml of sv, 3h-thymidineincorporation was decreased, but no marked differences were observed in the incorporation of 3h-uridine. the level of intracellular cyclic adenosine monophosphate (c-amp) was found to decrease in sv-treated cells. | 1977 | 15435 |
| flocculation of influenza virus by a neuraminidase inhibitor, neuraminin, produced by streptomyces sp. | | 1977 | 16382 |
| physiology and biochemistry of streptomycetes. viii. esterase activity and production of turimycin in cultures of streptomyces hygroscopicus ja 6599. | esterase in cell-free extracts of streptomyces hygroscopicus ja 6599 has a temperature-optimum of 35 degrees c, a ph-optimum with p-nitrophenylacetate as substrate at ph 7.7--8.1, with alpha-naphthylacetate at ph 7--9. michaelis constants in cell-free extracts: with alpha-naphthylacetate km = = 0.71 mm, with p-nitrophenylacetate km = 0.21 mm. phenylesters were better hydrolyzed than naphthylesters, phenylacetate was best hydrolyzed; beta-naphthylacetate was better hydrolyzed than alpha-naphthyla ... | 1977 | 16409 |
| alkaline serine proteinases d and e of streptomyces griseus k-1. | two dfp-sensitive alkaline proteinases with strong esterase activity toward ac-(ala)3-ome, designated as alkaline serine proteinases d and e, were purified pronase, a protease mixture from st. griseus k-1. each was shown to be homogeneous by acrylamide disc gel electrophoresis. the molecular weights of these enzymes were estimated to be about 27,000 be gel filtration. studies on their actions on acyl-tl-amino acid methyl or ethyl esters indicated that proteinases d and e both exhibited a broad s ... | 1977 | 16870 |
| identification of folate binding macromolecule in rabbit choroid plexus. | a macromolecular binder of folic acid and folic acid derivatives has been identified in the particulate fraction of homogenates of rabbit choroid plexus. within the choroid plexus, there are 2.3 nmol of folate-binding activity (binder) per g of tissue. the molecular weight of the folate binder complex, separated from the particulate fraction after solubilization with triton x-100, was 340,000 to 400,000 by sephadex gel filtration. the partially purified binder, when freed of endogenous folates, ... | 1977 | 16898 |
| effect of covalent attachment of polyethylene glycol on immunogenicity and circulating life of bovine liver catalase. | methoxypolyethylene glycols of 1900 daltons (peg-1900) or 5000 daltons (peg-5000) were covalently attached to bovine liver catalase using 2,4,6-trichloro-s-triazine as the coupling agent. rabbits were immunized by the intravenous and intramuscular routes with catalase modified by covalent attachment of peg-1900 to 43% of the amino groups (peg-1900-catalase). the intravenous antiserum did not yield detectable antibodies against peg-1900-catalase or native catalase, as determined by ouchterlony an ... | 1977 | 16907 |
| regulative influence of o-aminobenzoic acid on the biosynthesis of nourseothricin in cultures of streptomyces noursei ja 3890b. ii. regulation of glutamine synthetase and the role of the glutamine synthetase/glutamate synthase pathway. | | 1977 | 17950 |
| studies on the biosynthesis of 16-membered macrolide antibiotics using carbon-13 nuclear magnetic resonance spectroscopy. | the origin of the skeletal carbons in the lactone ring of 16-membered macrolide antiobiotics has been studied. 13c-labeled antibiotics leucomycin and tylosin, have been obtained from the culture broth of streptomyces kitasatoensis 66-14-3 and streptomyces fradiae c-373, respectively in the presence of appropriate 13c-labeled precursors, and 13c nmr spectra of the antibiotics thus obtained have been measured. it was shown that the aglycone of leucomycin a3 is derived from five acetates, one propi ... | 1977 | 18162 |
| studies related to antitumor antibiotics. part ix. reactions of carzinophillin with dna assayed by ethidium fluorescence. | the reactions of the antitumor antibiotic carzinophillin (cz) with native dnas and synthetic polynucleotides have been examined by an ethidium fluorescence assay. cz rapidly produces covalent linkage of the complementary strands of a variety of dnas without activation. this process is accompanied by extensive alkylation, as detected by reduced fluorescence due to destruction of potential intercalation sites for ethidium. these processes which occur without loss of purine or pyrimidine bases show ... | 1977 | 18267 |
| influence of amino acids on synthesis of extracellular proteases by actinomyces thermovulgaris. | various amino acids had different effect on the synthesis of exocellular proteases by actinomyces thermovulgaris t-54. glutamine and arginine induced the synthesis, the effect depending on their concentration in the medium. other amino acids inhibited the synthesis of proteases. the synthesis of alkaline and neutral proteases was not coordinated, and the ratio between these enzymes was not constant in different variants of the experiment. the maximum synthesis of alkaline proteases was found bef ... | 1977 | 18653 |
| studies on sterol-ester hydrolase from fusarium oxysporum. i. partial purification and properties. | 1. a search for a long chain fatty acyl sterol-ester hydrolase in microorganisms led to the isolation from soil of five strains belonging to fusarium sp. which produced strong activity in the culture medium. 2. the cholesterol esterase from fusarium oxysporum igh-2 was purified about 270-fold by means of cacl2 precipitation and sephadex g-75 column chromatography. 3. the cholesterol esterase was activated by adekatol and triton x-100. it was inhibited by lecithin and lysolecithin, and completely ... | 1977 | 19426 |
| interaction of thiolsubtilisin with streptomyces subtilisin inhibitor, ssi. | subtilisin bpn' was chemically converted to thiolsubtilisin and the interaction of this modified enzyme with streptomyces subtilisin inhibitor (ssi) was examined. ssi competitively inhibited the esterolytic activity of thiolsubtilisin toward p-nitrophenyl acetate with a k1 value of 1.3 x 10(-5) m at ph 7.5 spectrophotometric analysis of the interaction between ssi and the modified enzyme yielded a kd value of 4 x 10(-5) m at ph 9.7. these values are about 10(5)-fold greater than the kd value (le ... | 1977 | 19450 |
| bacterial metabolism of anthracycline antibiotics. steffimycinone and steffimycinol conversions. | streptomyces nogalater, uc-2783, and streptomyces peucetius var. caesius, imru-3920/uc-5633, catalyze ketonic carbonyl reduction of steffimycinone (1, scheme 1). using cell-free preparations of s. nogalater, the process of ketonic carbonyl reduction has been shown to be tpnh linked. the product, steffimycinol (2), is reduced further by aeromonas hydrophila, 2c/uc-6303, by the process of microaerophilic conversion of anthracyclinones previously reported1,2) with the result being the formation of ... | 1977 | 20436 |
| biosynthesis of polyene macrolide antibiotics. | | 1977 | 20831 |
| purity and ph-dependence of streptomyces griseus protease 1. | | 1977 | 21502 |
| proteolytic enzymes of the k-1 strain of streptomyces griseus obtained from a commercial preparation (pronase). effect of ph, metal ions, and amino acids on aminopeptidase activity. | | 1978 | 22544 |
| influence of inorganic phosphate and organic buffers on cephalosporin production by streptomyces clavuligerus. | a high concentration of potassium phosphate (75--100 mm) stabilized ph and supported extensive growth of streptomyces clavuligerus in a chemically defined medium; such a concentration also inhibited cephalosporin production. although tris buffer was found to have detrimental effects on growth and antibiotic production, 3-(n-morpholine)-propane sulfonate (mops) or 2-(np-morpholine)-ethane sulfonate (mes) buffer provided a nontoxic buffering system. in the presence of mops buffer, cephalosporin pr ... | 1977 | 23086 |
| characterization of l-aspartate uptake by streptomyces hydrogenans. | multiple transport systems for l-aspartic acid exist in steptomyces hydrogenans. the intracellular accumulation of l-aspartate against a concentration gradient was immediately inhibited by proton conductors, such as carbonyl cyanide p-trifluoromethoxyphenylhydrazone, 2,4-dinitrophenol or nigericin. transport activity was gradually lost when inhibitors of protein synthesis were added. l-aspartate transport had two ph optima at 6.5 and 4.5. at ph 6.5, two saturable transport components with differ ... | 1977 | 23409 |
| mycetoma in somalia - results of a survey done from 1959 to 1964. | the pasteur institute studied 103 mycetoma patients in somalia between 1959 and 1964. grains were seen in 94 of them and this, added to cultural features, allowed the diagnosis of 60 pathogens as follows: 44 madurella mycetomi, 1 leptosphaeria senegalensis, 7 pyrenochaeta romeroi (or madurella grisea), 3 allescheria boydii, 1 fusarium sp., 3 neotestudina (zopfia) rosatii, and 1 unidentified; 34 were actinomycetes: 24 streptomyces somaliensis, 4 actinomadura madurae, 3 a. pelletieri and 3 nocardi ... | 1977 | 23657 |
| microbiological transformation of carbohydrates. glucose isomerization into fructose by washed cells of streptomyces sp. strain 29. | glucose-fructose transformation by washed and packed cells of streptomyces sp. 29 was studied. the cells grown on the nutrient medium containing xylose and co and mg salts were capable to perform glucose-fructose isomerization. the cellular activity depended in a great degree on the temperature, ph and initial glucose concentration; to a lesser extent on co and mg ions present in the incubation mixture, and did not depend on the age of the culture (within 8-69 hours). the activity reached its ma ... | 1978 | 24842 |
| purification and characterization of lysozyme produced by streptomyces erythraeus. | a species of lysozyme (se lysozyme) was purified from culture filtrate of streptomyces erythraeus. the enzyme has a molecular weight of 18,500 as determined by ultracentrifugation. its isoelectric point is 9.5, and it shows optimal activity at ph 4.0 with an optimal ionic strength of 0.1. investigation of the substrate specificity showed se lysozyme to be an n-acetyl-muramidase. the simplest product in the digest of cell walls of micrococcus lysodeikticus was identified as a disaccharide, glcnac ... | 1978 | 25274 |
| immobilization of streptomyces flavochromogenes pullulanase on tannic acid and teae--cellulose. | pullulanase was immobilized successfully by simple, inexpensive methods that may be useful for industrial application of this enzyme. a tannin--pullulanase(tp) complex was obtained by addition of tannic acid to the culture filtrate of thermophilic streptomyces flavochromogenes. tp could be bound to teae--cellulose (ttcp). immobilization in this manner took place with quantitative retention of activity. the immobilized enzymes were stable for more than six months. the optimum temperatures of the ... | 1978 | 25683 |
| microbial metabolism of anthracycline antibiotics daunomycin and adriamycin. | it has been shown that the antitumor antibiotics daunomycin (1) and adriamycin (4) are metabolized by microorganisms in a fashion similar to their metabolism by mammalian cells. both the fungus mucor spinosus and its cell-free extracts reduce the 13-keto group of daunomycin to give daunomycinol (2) by a tpnh-dependent process. cell-free extracts of streptomyces steffisburgensis convert adriamycin and daunomycinol to their 7-deoxyaglycones (5) and (3) by dpnh-linked reductive glycosidic cleavage. ... | 1978 | 26650 |
| glutamate-induced uptake of proline by streptomyces antibioticus. | streptomyces antibioticus possesses an energy-dependent, carrier mediated transport system for the uptake of l-glutamate and l-proline. amino acid transport was found to have a temperature optimum of 35 degrees c and a ph optimum from 7.0 to 8.0 for glutamate and 6.5 to 7.5 for proline uptake. uptake did not depend upon mg2+, ca2+, zn2+, na+, or fe2+ ions. reversible p-hydroxymercuribenzoate inhibition of uptake indicated the involvement of an active sulfhydryl group. l-glutamate uptake was medi ... | 1978 | 26658 |
| acceptor specificity of atp:nucleoside-5'-phosphate pyrophosphotransferase from streptomyces adephospholyticus. synthesis of the 3'-pyrophosphates of pyrimidine nucleotides, some oligoribonucleotides, 5'-diphosphonucleosidic coenzymes and mg-5'-ppp-5'-am. | atp: nucleoside-5'-phosphate pyrophosphotransferase ec 2.7.6.4 of streptomyces adephospholyticus synthesizes not only 3'-pyrophosphates of 5'-purine ribomononucleotides but also those of pyrimidine mononucleotides, some short oligonucleotides, a variety of 5'-diphosphonucleosidic coenzymes and mg-5'-ppp-5'-am. | 1978 | 26674 |
| endo-beta-n-acetylglucosaminidase from streptomyces plicatus. | | 1978 | 26849 |
| origin of adifferentiated variants of streptomyces roseoflavus in submerged culture. | adifferentiated nocardia-like variants (nv) of streptomyces roseoflavus var. roseofungini, similar in their cultural characteristics with the variant 1-68 described elsewhere (nikitina, 1968; kalakoutskii a. nikitina, 1976), can be obtained not only in the course of growth of the parent culture on a solid medium containing fructose in the form of secondary colonies, but also during submerged cultivation with stirring. interruptions in aeration do not affect accumulation of the cells of such vari ... | 1978 | 26856 |
| immobilized form of streptomyces griseus proteases complex. | the immobilized form of proteases complex of str. griseus actinomycete is obtained by means of glutaric aldehyde with aminoethyl cellulose. hydrolysis of synthetic substrates showed that the system of peptide hydrolases is bound, but the ratio of activities as compared to the initial proteolytic complex changes, ph-optimum of the total proteolytic activity, ph- and temperature optima of stability are not changed with immobilization. on the whole no essential stabilization of the complex was obse ... | 1978 | 26997 |
| the influence of ph on the growth rate and viability of neutrophilic and acidophilic streptomycetes. | the influence of ph on the specific growth rates of two acidophilic and two neutrophilic soil streptomycetes was studied. the acidophiles had maximum growth rates over a broad range from ph 4.5 to 5.5, while the neutrophiles had clearly defined optima at ph 7.0. mycelium of neutrophiles was less tolerant of acidity than that of acidophiles; both showed decreased viability at ph levels below those which allowed growth. spores of neutrophiles and acidophiles were equally tolerant of acidity and th ... | 1978 | 27702 |
| screening for ph-dependent alpha-l-arabinofuranosidases in various representative strains of actinomycetales. | | 1978 | 27906 |
| glucose-isomerizing enzyme from actinomyces olivocinereus and its immobilization on aminosilochrome. | glucose-isomerizing enzyme was isolated from the culture of actinomyces olivocinereus. it was purified by the chromatography on deae-cellulose. the samples of glucose-isomerasing enzyme are homogeneous according to the results of analytical electrophoresis and ultracentrifugation. glucose-isomerase is more stable than soluble one. the ph-optima of soluble and immobilized enzymes are 8.5 and 7.5, respectively. the temperature optimum of immobilized enzyme, km, v, and activation energy do not chan ... | 1978 | 29676 |
| nad- and fad-3'-pyrophosphates--enzymic synthesis and inertness. | | 1978 | 30649 |
| [distribution of oleandomycin between the native broth and butylacetate depending on the biosynthesis conditions]. | distribution of the active substance contained in the fermentation broth of act. antibioticus between the acqueous phase and butylacetate depended on the fermentation conditions and the procedure for the fermentation broth treatment before filtration. increase in ph values during the fermentation process resulted in lower antibiotic distribution coefficients which may be explained by the presence of oleandomycin-x, a biologically active substance in the fermentation broth filtrates. this substan ... | 1978 | 31834 |
| deodorization of pig feces by actinomycetes. | peg feces, a malodorous substance causing environmental pollution, were completely deodorized within 2 days by streptomyces. the optimum conditions for deodorization were as follows: ph, 8.6 to 10; temperature, 35 to 40 degrees c; moisture content, 42 to 63%; and minimum amount of inoculum, 2 g of seed culture per 10 g of fresh feces. many kinds of microorganisms were isolated from the deodorized feces, of which only actinomycetes were found to have the ability to deodorize. two strains with str ... | 1978 | 31838 |
| affinity chromatography of trypsin and related enzymes. v. basic studies of quantitative affinity chromatography. | a detailed study of the quantitative affinity chromatography of trypsin [ec 3.4.21.4] is reported here. frontal chromatography using an enzyme solution of very low concentration on an affinity adsorbent gave the dissociation constant of the enzyme-immobilized ligand complex (kd). kd values determined under various conditions enabled us to discuss in detail the interaction of trypsin and affinity adsorbents (mainly gly-gly-arg sepharose). the ph dependence of kd was consistent with that of the in ... | 1978 | 32167 |
| direct fluorometric determination of a dissociation constant as low as 10(-10) m for the subtilisin bpn'--protein proteinase inhibitor (streptomyces subtilisin inhibitor) complex by a single photon counting technique. | it was found that an increase in fluorescence intensity at 340 nm is observed on the binding of streptomyces subtilisin inhibitor (ssi) with subtilisin bpn' in the ph range 6--10. the dissociation constant, ki, of the enzyme-inhibitor complex was determined as a function of ph and temperature by direct fluorometric titration utilizing the single photon counting technique in the protein concentration range of 10(-9) m. ki values as low as 10(-10) m could be obtained with reasonable accuracy by th ... | 1978 | 32173 |
| the influence of ph on starch hydrolysis by neutrophilic and acidophilic streptomycetes. | the effect of ph on the starch hydrolysing activity of one neutrophilic and two acidophilic soil streptomycetes was studied in detail. the neutrophilic culture extract was active from ph 5.0 to ph 8.0, with optimum activity from ph 5.5 to 6.5. acidophile activity occurred from ph 2.5 to 7.0 with an optimum at ph 4.0 to 4.5. after storage for 24 h at different ph levels, neutrophiles showed a sharp reduction in activity at ph 5.0 with none below this point; some activity was maintained up to ph 1 ... | 1978 | 32464 |
| regulative influence of o-aminobenzoic acid on the biosynthesis of nourseothricin in cultures of streptomyces noursei ja 3890b. iii. change of redox state of nicotinamide-adenine-dinucleotides in the presence of aminobenzoic acids. | o-aminobenzoic acid (oaba, anthranilic acid) and related compounds which are known to stimulate the biosynthesis of streptothricin-type antibiotic nourseothricin by streptomyces noursei ja 3890b were found to increase strongly the nadh/nad+ ratio in growing mycelium of this strain suggesting that these effectors are capable of interfering with the function of the respiratory chain. in parallel, a complex shift of metabolism was induced shown by simultaneous alteration of mycelial activities of a ... | 1978 | 32666 |
| isolation of type-specific polysaccharide antigen from group b type ib streptococci. | group b streptococcus type ib (strain h36b) was subjected to digestion with extracellular muralytic enzymes prepared from streptomyces albus. type ib-specific polysaccharide antigen was isolated from the lysate by alcohol precipitation and sepharose 6b chromatography. the purified type ib antigen has a kd value of 0.31 on a sepharose 4b column and contains four sugars, galactose, glucose, n-acetyl glucosamine, and sialic acid in a molar ratio of 2.05:0.86:1.00:0.90. acid treatment (ph 2.0) of th ... | 1979 | 33225 |
| nitroalkane oxidation by streptomycetes. | crude cell-free extracts of nine strains of streptomyces tested for nitroalkane-oxidizing activity showed production of nitrous acid from 2-nitropropane, 1-nitropropane, nitroethane, nitromethane, and 3-nitropropionic acid. these substrates were utilized in most strains but to a decreasing extent in the order given, and different strains varied in their relative efficiency of oxidation. p-nitrobenzoic acid, p-aminobenzoic acid, enteromycin, and omega-nitro-l-arginine were not attacked. d-amino a ... | 1979 | 33965 |
| maleylation and ph-dependence of streptomyces griseus protease b. | the enzymatic activity of streptomyces griseus protease b (sgpb) was measured over ph range 8.4--11.5 using a specific new, chromophoric substrate n-succinyl-glycyl-glycyl-l-phenylalanine p-nitroanilide. it was found that the activity is dependent on ionization of a single group with apparent pk = 10.84, possibly lysine-125. maleylation of the epsilon-amino group of this lysine was linearily associated with the loss of enzymatic activity. it is therefore suggested that the electrostatic interact ... | 1979 | 34571 |
| mammalian and microbial cell-free conversion of anthracycline antibiotics and analogs. | cell-free preparations of streptomyces nogalater and rat liver catalyze reduced pyridine nucleotide dependent conversion of nogalamycin to 7-deoxynogalarol and nogalose (scheme 1). the mammalian process requires tpnh and has a specific activity of 85 nmoles of 7-deoxynogalarol formed per hour per mg of protein while the bacterial process prefers dpnh and has a specific activity of 5. the oxygen-sensitive conversions have ph optima of 7.5 (rat) and 9 (s. nogalater). other anthracycline substrates ... | 1979 | 35508 |
| further studies on the interaction between a protein proteinase inhibitor, streptomyces subtilisin inhibitor, and thiolsubtilisin bpn'. | | 1979 | 36373 |
| [aminoglycoside-3'-phosphotransferase from actinomyces fradiae. its isolation, purification and properties]. | aminoglycoside phosphotransferase was isolated from the mycelium of act. fradiae, the neomycin-producing organism, with paromomycin, neomycin and to a less extent ribostamycin being substrates of aminoglycoside-phosphotransferase. it was purified to homogenous state. the maximum activity of the enzyme preparations was observed at ph 7.7--7.8;km for neomycin and paromomycin was about 20 micron and km for atp was 150 micron. mg2+ ions were necessary for the enzyme activity. none of the divalent ca ... | 1979 | 36832 |
| [aminoglycoside-3'-phosphotransferase from actinomyces fradiae. the identification of its inactivation product]. | neomycin phosphate was obtained as a result of neomycin phosphorylation with aminoglycoside-phosphotransferase from act. fradiae. it was isolated from the reaction mixture and purified. successive ion exchange chromatography on columns with amberlite irc-50 (nh+4 form), dowex 1 x 10 (oh- form) and amberlite cg-50 (nh+4 form) was used for purification of the inactivation product. the findings of the elementary analysis of neomycin phosphate showed the presence of 1 mole of phosphorus per 1 mole o ... | 1979 | 36833 |
| partial purification and properties of glucosyltransferase from streptomyces aureofaciens. | differential centrifugation, precipitation with ammonium sulphate and chromatography on deae-cellulose led to a twenty-fold purification of glucosyltransferase from streptomyces aureofaciens b 96. the michaelis constants for glucosyluridyl diphosphate (udp-glucose) was 10.8 microm for 1,2-dihydroxy-9,10-anthraquinone (alizarin) 110 microm; the maximum rate of glucosylation reaction was 5.32 mumol per s per mg protein. the ph optimum was at 7.1; the flat temperature optimum was at 30 degrees c. u ... | 1979 | 38193 |
| myo-inositol-1-phosphate synthase from streptomyces griseus (studies on the biosynthesis of cyclitols, xxxviii). | it could be shown that streptomyces griseus, the microorganism producing the antibiotic streptomycin and also mutant strains of this species that cannot synthesize streptomycin, possess myo-inositol-1-phosphate synthase (ec 5.5.1.4), the enzyme cyclizing d-glucose 6-phosphate. the enzyme isolated from that organism is extremely instable, its molecular weight is approximately 260,000, and it requires a divalent metal ion for its activity. this is the first instance that an enzyme of this specific ... | 1979 | 38395 |
| [properties of immobilized complexes of streptomyces griseus proteases on different carriers]. | a complex of str. griseus proteases was obtained. the proteases were immobilized on sephadex g-200 and agarose by the bromo-cyanogen method and on the microcrystalline cellulose by means of ticl3. the enzymic complex immobilized on different carriers possesses the proteolytic activity of a wide specificity. due to addition to different carriers the activity of certain enzymes producing the complex varies. the immobilized complex is shown to be more stable in the alkaline zone. the immobilized co ... | 1979 | 38547 |
| purification and properties of a proteinaceous metallo-proteinase inhibitor from streptomyces nigrescens tk-23. | a novel metallo-proteinase inhibitor which is capable of inhibiting the activities of metallo-proteinases such as the thermolysin, was isolated from the culture filtrates of streptomyces nigrescens tk-23. the inhibitor was purified batch-wise from the culture filtrate by amberlite irc-50 and column chromatographies on cm-sephadex c-50 and sephadex g-50. the purified inhibitor showed a single band on 15% polyacrylamide gel electrophoresis at ph 4.3, and at ph 7.5 on sds-gels. the inhibitor retain ... | 1979 | 40611 |
| conditions for the appearance of adifferentiated nocardioform variants of streptomyces roseoflavus var. roseofungini. | it was shown that adifferentiated nocardioform variants (nv) of streptomyces roseoflavus var. roseofungini 1128 may appear in mycelial cell suspensions of submerged actinomycete cultures in water, phosphate buffer, and water with fructose (1%) or glucose (1%), as well as in mycelia of old (10-30 days) cultures on different carbon sources. when sugars, alcohols, or amino acids were added to a medium with fructose, nv formation was inhibited, but not completely suppressed. fructose was shown to be ... | 1978 | 40620 |
| purification and some properties of a new metallo carboxypeptidase of streptomyces griseus k-1. | | 1979 | 41837 |
| evolution of enzyme structure. | three-dimensional structures of enzymes offer evidence about their evolution. there are clear examples of divergent families (e.g. mammalian serine proteases) and convergence (e.g. chymotrypsin and subtilisin). topological similarities in dehydrogenases may reflect an ancient divergence or merely chemical constraints on protein architectures. further experimental evidence is desirable to back up arguments based on molecular morphology. by growing microorganisms on novel foodstuffs in a chemostat ... | 1979 | 42054 |
| biosynthesis of leupeptin. ii purification and properties of leupeptin acid synthetase. | an enzyme which condenses acetyl-l-leucyl-l-leucine and l-arginine into acetyl-l-leucyl-l-leucyl-l-leucyl-l-arginine (leupeptin acid) was partially purified from a cell extract of streptomyces roseus ma839-a1. with respect to this catalytic activity, the enzyme showed the following characteristics: atp is essential; optimum ph is 9.5; the activity is inhibited either by edta or pyrophosphate or n-ethylmaleimide. the molecular weight of the enzyme is about 260,000 daltons. it also catalyzes some ... | 1979 | 43319 |
| production of l-asparaginase by streptomyces karnatakensis and streptomyces venezuelae. | production of l-asparaginase by two soil isolates, identified as s. karnatakensis and s. venezuelae, was investigated under different environmental and nutritional conditions. the presence of carbon sources, other than starch, in the growth medium or amino acids, other than l-asparagine-inhibited the enzyme biosynthesis. l-aspartic inhibited growth and enzyme production, due to a feedback mechanism, and/or lowering the ph value. both organisms were stimulated to produce more enzyme with increasi ... | 1979 | 44413 |