| the influence of ph on the interaction of inhibitors with triosephosphate isomerase and determination of the pka of the active-site carboxyl group. | ionization effects on the binding of the potential transition state analogues 2-phosphoglycolate and 2-phosphoglycolohydroxamate appear to be attributable to the changing state of ionization of the ligands themselves, therefore it is unnecessary to postulate the additional involvement of an ionizing residue at the active site of triosephosphate isomerase to explain the influence of changing ph on ki in the neutral range. the binding of the competitive inhibitor inorganic sulfate is insensitive t ... | 1975 | 47 |
| subunit interactions in yeast glyceraldehyde-3-phosphate dehydrogenase. | the spontaneous inactivation of yeast glyceraldehyde-3-phosphate dehydrogenase was found to fit a simple two-state model at ph 8.5 and 25 degrees. the first step is a relatively rapid dissociation of the tetramer to dimers with the equilibrium largely in favor of the tetramer. in the absence of nad+ the dimer inactivates irreversibly. the apoenzyme is quite stable with a half-life for complete activity loss proportional to the square root of the enzyme concentration. perturbances of the protein ... | 1975 | 55 |
| yeast glutathione reductase. studies of the kinetics and stability of the enzyme as a function of ph and salt concentration. | 1. the ph dependencies of the apparent michaelis constant for oxidized glutathione and the apparent turnover number of yeast glutathione reductase (ec 1.6.4.2) have been determined at a fixed concentration of 0.1 mm nadph in the range ph 4.5--8.0. between ph 5.5 and 7.6, both of these parameters are relatively constant. the principal effect of low ph on the kinetics of the enzyme-catalyzed reaction is the observation of a ph-dependent substrate inhibition by oxidized glutathione at ph less than ... | 1975 | 74 |
| temperature and ph optima for 21 species of thermophilic and thermotolerant fungi. | a glucose-containing mineral medium supplemented with 0.01% yeast extract is described upon which all the species of thermophilic and thermotolerant fungi tested will grow. thirteen of the 21 species do not require the yeast extract supplement for growth. using this solid, supplemented mineral medium, the ph and temperature optima for growth of all strains were measured. no correlation was found between temperature optimum and ph optimum among members of the group tested. | 1975 | 138 |
| 5-carbamoylmethyluridine: a new minor nucleoside of transfer ribonucleic acid. | | 1975 | 264 |
| gastric ph and microflora of normal and diarrhoeic infants. | the microflora and ph of gastric contents were determined in breast-fed and in bottle-fed normal infants, in well nourished infants with acute diarrhoea and in infants with chronic diarrhoea and protein-calorie malnutrition. the last group of infants was reevaluated after recovery from diarrhoea and protein-calorie malnutrition. a bactericidal ph effect below 2-5 was observed. bottle-fed controls had low ph values and low bacterial concentrations, whereas infants with chronic diarrhoea and prote ... | 1975 | 274 |
| effect of some aldoses on growth of saccharomyces cerevisiae inhibited with molybdenum. | the inhibitory effect of molybdenum ions on growth of yeasts at ph 5.5 was found to be decreased by aldoses in the following order: d-talose greater than l-mannose greater than l-ribose greater than d-lyxose greater than l-galactose greater than l-arabinose greater than l-glucose greater than l-xylose. increased concentrations of molybdenum brought about morphological changes of yeast cells. cells grown under these conditions were smaller, had thicker walls and formed clusters. | 1975 | 285 |
| transport of 4-deoxy- and 6-deoxy-d-glucose in baker's yeast. | tritium-labelled 4-deoxy-d-glucose (4-dglc) and 6-deoxy-d-glucose (6-dgcl) were prepared by catalytic hydrogenolysis of the corresponding deoxyiodo derivatives with gaseous tritium. the two sugars are transported into saccharomyces cerevisiae by both the constitutive glucose and the inducible galactose carrier. uranyl ions are powerful inhibitors. the ph optimum in uninduced cells lies at 5.5 for both sugars, the apparent activation energies (between 15 and 35 degrees c) are 25.1 kj/mol and 16.5 ... | 1975 | 287 |
| phospholipase d activity of gram-negative bacteria. | a phospholipase hydrolyzing cardiolipin to phosphatidic acid and phosphatidyl glycerol was characterized in gram-negative bacteria but was absent in preparations of gram-positive bacteria, saccharomyces cerevisiae, and rat liver mitochondria. in cell-free extracts of escherichia coli, salmonella typhimurium, proteus vulgaris, and pseudomonase aeruginosa, this cardiolipin-hydrolyzing enzyme had similar ph and mg2+ requirements and displayed a specificity which excluded phosphatidyl glycerol and p ... | 1975 | 360 |
| simple and sensitive procedure for screening yeast mutants that lyse at nonpermissive temperatures. | after mutagenesis, surviving yeast cells are grown on plates at 25 c and later exposed to 37 c. the plates are then overlaid with a soft agar containing p-nitrophenylphosphate at ph 9.7. lysed cells liberate alkaline phosphatase which gives rise to a yellow color on and around colonies. | 1975 | 372 |
| manganese mutagenesis in yeast. a practical application of manganese for the induction of mitochondrial antibiotic-resistant mutations. | when yeast cells were incubated for 4 to 8 h in yeast extract-peptone-glucose medium, ph 6, containing 8 mm-manganese, and then plated on selective media, there was a strong induction of antibiotic-resistant mutations. indirect evidence suggests that practically all resistant mutants selected were of independent origin. the analysis of manganese-induced resistant mutants showed that most were extranuclear, while those tested showed recombination with known mitochondrial markers. our results sugg ... | 1975 | 464 |
| methods for avoiding proteolytic artefacts in studies of enzymes and other proteins from yeasts. | | 1975 | 589 |
| induction of haploid glycoprotein mating factors in diploid yeasts. | | 1975 | 590 |
| induction, selection, and experimental uses of temperature-sensitive and other conditional mutants of yeast. | | 1975 | 591 |
| biosynthesis of flavins and its regulation in the yeast pichia guilliermondii. | the nature of riboflavin precursors was studied in the yeast pichia guilliermondii. by means of mutants with blocked gmp-synthetase the purine precursors of riboflavin were shown to belong to guanylic compounds. accumulation of 2,4,5-triamino-6-oxypyrimidine, 2,5-diamino-6-oxy-4-ribitylaminopyrimidine, 2,6-dioxy-5-amino-4-ribitylaminopyrimidine (doarap) and 6,7-dimethyl-8-ribityllumasine occurs in the riboflavin-deficient mutants divided into five biochemical groups. this fact evidences for iden ... | 1975 | 834 |
| isoionic titration and isopycnic density gradient centrifugation studies of magnesium activation and subunit dissociation in yeast enolase. | | 1975 | 961 |
| enzymatic synthesis and reactions of uridine 5'-(5-thio-alphad-glucopyranosyl pyrophosphate). | | 1975 | 970 |
| evidence for an acetyl-enzyme intermediate in the action of acetyl-coa synthetase. | | 1975 | 1023 |
| glucanases in schizosaccharomyces. isolation and properties of an exo-beta-glucanase from the cell extracts and culture fluid of schizosaccharomyces japonicus var. versatilis. | (11 cell extracts and extracellular culture fluids of species of the yeast genus schizosaccharomyces exhibited exo-beta-(1 leads to 3)- and exo-beta-(1 leads to 6)-glucanase (ec 3.2.1.-) activities. (2) using a combination of sephadex g-100 and deae-cellulose chromatography, the exo-beta-(1 leads to 3)-glucanases from the cell extracts and culture fluid of schizosaccharomyces japonicus var. versatilis were purified extensively. the enzymes from either location exhibited similar purification and ... | 1975 | 1093 |
| yeast hexokinase a. succinylation and properties of the active subunit. | yeast hexokinase a (atp:d-hexose 6-phosphotransferase, ec2.7.1.1) dissociates into its subunits upon reaction with succinic anhydride. the chemically modified subunits could be isolated in a catalytically active form. the km values found for atp and for glucose were of the some order as those found for the native enzyme. of the 37 amino groups present per enzyme subunit, 2-3 of these groups might be located in the proximity of the region of subunit interactions. the 50% loss of the initial activ ... | 1975 | 1253 |
| hepatic nucleases. extrahepatic origin and association of neutral liver ribonuclease with lysosomes. | in the large granule fraction of rat liver, the density distribution of inhibitor-sensitive neutral ribonuclease is similar to that for acid hydrolases and its density distribution is similarly modified by triton wr-1339 accumulation in lysosomes. particulate neutral ribonuclease is latent; the enzyme is unmasked by very low digitonin concentrations or hypoosmotic shock. these observations demonstrate that the bulk of liver neutral ribonuclease is associated with the lysosomal system. in view of ... | 1975 | 1273 |
| studies on cytochrome oxidase. partial resolution of enzymes containing seven or six subunits, from yeast and beef heart, respectively. | highly active, essentially homogeneous, preparations of ferrocytochrome c oxidase (ec 1.9.3.1) have been obtained from both yeast and beef heart by extraction with cholate, fractionation with ammonium sulfate, and replacement of cholate by tween 20. the molecular weights of the resultant proteins equal 260 +/- 23 x 10(3) and 205 +/- 10(3); they contain seven and six different polypeptide subunits, respectively, all in equimolar amounts, with apparent molecular weights of 42.4, 34.1, 24.7, 14.6, ... | 1976 | 1385 |
| isolation of penicillium corylophium dierckx from acid mine water and its optimal growth on hydrocarbons at acid ph. | penicillium corylophilium dieckx was isolated from sludge collected at the interface of an aqueous, copper-bearing leachate and an organic, kerosene based, ion exchange solvent. the organism assimilated kerosene and various straight chain and cyclic hydrocarbons including dodecane, hexadecane, octadecane, toluene, benzene, and cyclohexane. assimilation of kerosene and hexadecane was optimal at ph 2 and was stimulated by yeast extract. | 1975 | 1676 |
| effect of cultivation conditions on the synthesis of citric and isocitric acids in candida lipolytica on hexadecane medium. | the influence of aeration, ph and iron concentration on the growth of yeast c. lipolytica 704 on the hexadecane medium and on the synthesis of citric and isocitric acids was investigated. the yeast synthesized citric acids actively during intensive aeration. the acid formation was strongly dependent on the medium acidity: ph 6.0 was most favourable for the synthesis of citric acids. the fe concentration influenced significantly the ratio of the acids synthesized. at a low concentration of iron ... | 1975 | 1720 |
| study of the yeast dissolving enzymic complex by isoelectric focusing. | by isoelectric focussing the lyzing complex produced by actinomyces griseinus-11 has been fractionated. the sole neutral protease which is active at ph 7.0 does not participate in lysis induced by other enzymes. the lyzing activity of this complex is associated with the carbohydrase enzymes that are at least three in number. various carbohydrases may exert a synergistic effect upon their combined action on the protein-vitamin concentrate. | 1975 | 1723 |
| isolation and basic properties of thiamine pyrophosphokinase from brewing yeast. | thiamine pyrophosphokinase (ec 2.7.7.2) isolated from dry brewing yeast has been purified 20-fold with a 70% yield. certain properties of the enzyme have been determined: ph and temperature optima, donor and acceptor concentrations, and relationship between the rate of cocarboxylase biosynthesis and the incubation time and the enzyme quantity. the effects of concentrations of bivalent metal ions co2+, mg2+ and mn2+ on the rate of the enzymic reaction has been studied. a change in the ph optimum ... | 1975 | 1724 |
| effect of ph on the properties of the chemostatic culture of canida utilis. | the effect of hydrogen and hydroxyl ions on the physiological features of the yeast c. utilis vkmu-1668 was studied. high acidity inhibited yeast growth and uncoupled pathways of the energy and constructive metabolism: normal respiration was disturbed and the electron transport chain was damaged in the site of cytochromes and not flavins. hydroxyl ions also inhibited yeast growth and uncoupled pathways of the energy and constructive metabolism: oxygen uptake and the content of flavin adenone din ... | 1975 | 1727 |
| purification of glutamine synthetase from the yeast candida tropicalis. | | 1975 | 1728 |
| activation of l-amino acids by aminoacyl-trna-synthetases from yeast candida utilis ibpm-405. | the procedure for isolating aminoacyl-trna-synthetases from yeast candida utilis ibpm-405 was developed. the rate of activation of l-amino acids in the formation of hydroxamates was different. aspartic acid, asparagine, glutamic acid, tryptophane, phenyl alanine and methionine underwent the highest activation. the activation of alanine, arginine, hydroxyproline, serine and isoleucine was insignificant. using aspartic acid, it was shown that the hydroxamate formation was atp-stimulated and that t ... | 1975 | 1729 |
| lactose hydrolysis by yeast beta-galactosidase. | | 1975 | 1730 |
| regulation of glutamine synthetase of the fodder yeast candida tropicalis by ammonium ions. | the effect of ammonium on glutamine synthetase of fodder yeast candida tropicalis was studied. ammonium ions were found to repress the synthesis of glutamine synthetase of fodder yeast and to inhibit the enzyme in the cells. the substitution of glutamic acid for ammonium in the nutrient medium brought about depression of glutamine synthetase. | 1975 | 1735 |
| high resolution 31p nuclear magnetic resonance studies of intact yeast cells. | high resolution 31p nuclear magnetic resonance (nmr) spectra at 145.7 mhz are presented for intact yeast cells. several peaks are resolved and assigned. they include the middle phosphate peaks from long chain or cyclic polyphosphates. our results are consistent with the suggestion that these polyphosphates act as a phosphate store in the cell. we have also been able to measure cytoplasmic ph using the orthophosphate peak inside the cell, as compared with outside the cell. the results show that y ... | 1975 | 1747 |
| evidence that acyl coenzyme a synthetase activity is required for repression of yeast acetyl coenzyme a carboxylase by exogenous fatty acids. | the cellular content of acetyl-coa carboxylase acetyl-coa:carbon-dioxide ligase (adp-forming), ec 6.4.1.2 in saccharomyces cerevisiae is reduced by the addition of long-chain fatty acids to the culture medium. mutant strains of s. cerevisiae defective in acyl-coa synthetase acid:coa ligase (amp-forming), ec 6.2.1.3 were isolated and used to determine whether fatty acid itself or a metabolite of fatty acid is more directly responsible for the repression of acetyl-coa carboxylase. cells of the mut ... | 1976 | 1754 |
| specific p-nitrophenyl phosphatase of yeast pichia guilliermondii. | the cells of yeast p. guilliermondii contain specific p-nitrophenyl phosphatase (pnppase), the level of which depends on the cells supply with inorganic phosphorus. partially purified enzyme is activated by ions mg2+, co2+ and somewhat weaker -- by ions fe2+. with the presence of mg2+ the enzyme activity is inhibited by ions cd2+, zn2+, f-, be2+, cu2+, mn2+, ca2+, moo42-, fe3+, fe2+, inorganic phosphate as well as by edta. a mixture ions be2+ and f- causes a complete inhibition of the activity. ... | 1975 | 1885 |
| chemistry and biology of macromolecular inhibitors from yeast acting on proteinases a and b, and carboxypeptidase y. | | 1975 | 1974 |
| protein staining and ph gradient determination on the same gel in isoelectric focusing. | | 1975 | 2031 |
| regulation of citrate synthase activity of saccharomyces cerevisiae. | citrate synthase activity of saccharomyces cerevisiae was determined by a radioactive assay procedure and the reaction product, 14c-citric acid, was identified by chromatographic techniques. atp, d-atp, gtp and nadh were most inhibitory to the citrate synthase invitro. the activity was inhibited to a lesser extent by adp, utp, and nadp whereas, amp and ctp were much less inhibitory. nadh, like nad, glutamic acid, glutamine, arginine, ornithine, proline, aspartic acid and alpha-ketoglutarate exhi ... | 1975 | 2100 |
| cross partition and determination of net charge of the isoenzymes of enolase. | enolase from bakers' yeast was separated into three isoenzymes by countercurrent distribution. the isoenzymes were partitioned in aqueous polymer two-phase systems containing positively charged trimethylamino poly(ethylene glycol) or negatively charged poly(ethylene glycol) sulphonate. the plots of the partition coefficient of each isoenzyme versus ph in the two biphasic systems intersect at ph equal to the isoelectric point. from slopes of the plots, the net charge of the isoenzymes at ph 6.57 ... | 1976 | 2297 |
| studies on the microsomal electron-transport system of anaerobically grown yeast. iii. spectral characterization of cytochrome p-450. | a carbon monoxide-binding pigment which shows an absorption peak at about 450 nm in the reduced carbon monoxide difference spectrum was purified from the microsomal fraction of yeast grown anaerobically. the spectral characteristics of the pigment were practically identical with those of cytochrome p-450 of hepatic microsomes, especially from polycyclic hydrocarbon-induced animals. the pigment was denatured to p-420, and bound with ethyl isocyanide in the reduced state. although type i spectral ... | 1975 | 2585 |
| transport and metabolism of vitamin b6 in the yeast saccharomyces carlsbergensis 4228. | active transport of pyridoxine, pyridoxal, and pyridoxamine occurs in resting cells of saccharomyces carlsbergensis 4228 and can lead to intracellular concentrations of free vitamin much higher than those supplied externally. the initial km for pyridoxine uptake is 3.6 x 10(-7) m at 30 degrees and ph 4.5, which are optimum for growth. transport is inhibited by many unphosphorylated vitamin analogs, the most effective being 5'-deoxypyridoxine, 5'-deoxypridoxal, toxopyrimidine, 4'-deoxypyridoxine, ... | 1976 | 2598 |
| correlation of the kinetics of electron transfer activity of various eukaryotic cytochromes c with binding to mitochondrial cytochrome c oxidase. | 1. a detailed study of cytochrome c oxidase activity with keilin-hartree particles and purified beef heart enzyme, at low ionic strength and low cytochrome c concentrations, showed biphasic kinetics with apparent km1 = 5 x 10(-8) m, and apparent km2 = 0.35 to 1.0 x 10(-6) m. direct binding studies with purified oxidase, phospholipid-containing as well as phospholiptaining aid-depleted, demonstrated two sites of interaction of cytochrome c with the enzyme, with kd1 less than or equal to 10(-7) m ... | 1976 | 2600 |
| microorganisms and characteristics of laban. | laban had a titratable acidity of about 1.0%, a ph of 4.25, an ethanol content of 1.25%, and contained 4.2 mug acetaldehyde and 34 mug acetoin/ml. there was no diacetyl. five microorganisms, classified as streptococcus thermophilus, lactobacillus acidophilus, leuconostoc lactis, kluyveromyces fragilis, and saccharomyces cerevisiae, were responsible for the fermentation. streptococcus thermophilus and l. acidophilus were responsible for acid production with s. thermophilus producing acid more rap ... | 1976 | 2630 |
| the determination of stability constants from small-angle x-ray scattering data and the analysis of ph-dependent macromolecular equilibria. | | 1975 | 2784 |
| effect of the nitrogen source in the medium on the activity of glutamine synthetase in candida tropicalis and on the kinetics of the enzymatic reaction of glutamine synthesis. | the effect of various nitrogen sources (l-glutamic acid, l-glutamine, l-aspartic acid, l-asparagine, and ammonium sulphate) on the synthetase and transferase activity of glutamine synthetase was studied in candida tropicalis. these nitrogen sources had different effect on the two activity of the enzyme. glutamic acid or ammonium sulphate did not produce any considerable action on the kinetic properties of glutamine synthetase of this fodder yeast. | 1975 | 2839 |
| interrelationship between the intestinal microflora of lackey moth, brown-tail moth and the entomopathogenic bacterium bacillus thuringiensis. | the interrelationship between the intestine microflora of lackey moth (malacosoma neustria l.), brown-tail moth (nygmia phaeorrhoea l.) and entomopathogenic bacteria bacillus thuringiensis (berl.), bac. thuringiensis var. galleriea, and bac. thuringiensis kr3 was studied in vitro. various organisms of the intestine microflora of lackey moth display bacteriostatic action towards bac. thuringiensis var. galleriea and bac. thuringiensis kr3 which is not typical of the microflora of brown-tail moth ... | 1975 | 2842 |
| myo-inositol oxygenase from oat seedlings. | enzyme preparations from oat seedlings showing the activity of myo-inositol oxygenase (e.c.1.13.99.1) have been described previously. in contrast to myo-inositol oxygenase preparations from other sources, e.g. rat kidney or yeast, the oat enzyme seemed to exhibit a somewhat less stringent activity, acting on other inositols and inositol methyl ethers as well as on myo-inositol. by purification of the enzyme present in the extract from oat seedlings with the help of an affinity gel specific for e ... | 1976 | 2857 |
| the effects of salicylic acid on metabolism and potassium ion content in yeast. | under anaerobic conditions, at low ph and 30 degrees, commercial baker's yeast loses k+ ion in the presence of salicylic acid. glucose utilization is inhibited. in suspensions containing no glucose, carbohydrate stores of the cell are dissimilated to carbon dioxide and alcohol. the ion loss and inhibitory effects of salicylic acid on glucose utilization are reversed by washing the cells free of salicylate. the loss of k+ appears to be due at least partly to a k+-h+ exchange process. an unexplain ... | 1976 | 2932 |
| deoxyribonucleic acid polymerases of euglena gracilis. primer-template utilization of and enzyme activities associated with the two deoxyribonucleic acid polymerases of high molecular weight. | the two high-molecular-weight dna polymerases from euglena gracilis, pol a (mol. wt. 190 000) and pol b (mol. wt. 240 000), were differentiated on the basis of associated enzymic activities and primer-template utilization. neither enzyme had endodeoxyribonuclease activity, but pol b, like pol b of yeast and the corresponding enzyme from tetrahymena pyriformis, exhibited at least one other nuclease activity directed against denatured dna and the rna of an rna-dna hybrid. these nuclease functions ... | 1975 | 3162 |
| enzyme-catalyzed redox reactions with the flavin analogues 5-deazariboflavin, 5-deazariboflavin 5'-phosphte, and 5-deazariboflavin 5'-diphosphate, 5' leads to 5'-adenosine ester. | the ability of 5-deazaisoalloxazines to substitute for the isoalloxazine (flavin) coenzyme has been examined with several flavoenzymes. without exception, the deazaflavin is recognized at the active site and undergoes a redox change in the presence of the specific enzyme substrate. thus, deazariboflavin is reduced catalytically by nadh in the presence of the beneckea harveyi nad(p)h:(flavin) oxidoreductase, the reaction proceeding to an equilibrium with an equilibrium constant near unity. this i ... | 1976 | 3207 |
| urea transport-defective strains of saccharomyces cerevisiae. | experiments characterizing the urea active transport system in saccharomyces cerevisiae indicate that (i) formamide and acetamide are strong competitive inhibitors of urea accumulation, (ii) uptake is maximal at ph 3.3 and is 80% inhibited at ph 6.0, and (iii) adenosine 5'-triphosphate generated by glycolysis in conjunction with formation of an ion gradient is likely the driving force behind urea transport. mutant strains were isolated that are unable to accumulate urea at external concentration ... | 1976 | 3491 |
| hydrogen exchange at the amide group of reduced pyridine nucleotides and the inhibition of that reaction by dehydrogenases. | stopped flow ultraviolet spectroscopy has been used to measure the rate of hydrogen exchange with solvent at the amide group of reduced nicotinamide nucleotide coenzymes. several mechanisms for the exchange reaction are considered in the light of the kinetic data. complex formation between the coenzyme and any of four dehydrogenases markedly slows the rate of hydrogen exchange. hydrogen bond formation and/or hydrophobic interactions within these complexes are thought to be the reasons for the de ... | 1976 | 3505 |
| yeast glutathione reductase. steady-state kinetic studies of its transhydrogenase activity. | | 1976 | 4035 |
| salt induced deprotonation of initially salt-free transfer rna. | | 1976 | 4068 |
| kinetics of ion translocation across charged membranes mediated by a two-site transport mechanism. effects of polyvalent cations upon rubidium uptake into yeast cells. | (1) the effect of surface charge upon the kinetics of monovalent cation translocation via a two-site mechanism is investigated theroretically. (2) according to the model dealt with, typical relations are expected for the dependence of the kinetic parameters of the translocation process upon the concentration of a polyvalent cation, differing essentially from those derived for the case in which the membrane carries no excess charge. (3) even when a polyvalent cation does not compete with the subs ... | 1976 | 4106 |
| anomalous fluorescence of yeast 3-phosphoglucerate kinase. | the 3-phosphoglycerate kinase (ec 2.7.2.3) of yeast which contains two tryptophyl and eight tyrosyl residues per molecule, displayed an unusualy fluorescence emission spectrum with a maximum at 308 nm when excited at 280 nm. the emission peak shifted to 329 nm when excited at 295 nm. we could confirm that it was due to the efficient quenching of tryptophyl fluorescence as well as to the incomplete energy transfer from tyrosyl to tryptophyl residues. the average fluorescence quantum yield of this ... | 1976 | 4108 |
| purification and properties of nadp-dependent glutamate dehydrogenase from yeast nuclear fractions. | 1. nadp-dependent glutamate dehydrogenase (ec 1.4.1.4) extracted from nuclear fractions of saccharomyces cerevisiae was partially purified. the final purification achieved was over 100-fold over the initial extract. 2. cellulose acetate electrophoresis shows that the preparation is close to homogeneity and that the enzyme is slightly more anionic than cytoplasmic glutamate dehydrogenase. 3. the response of the nuclear activity to variation of ph, of inorganic phosphate and other electrolyte conc ... | 1976 | 4126 |
| complete purification and studies on the structural and kinetic properties of two forms of yeast valyl-trna synthetase. | two forms of baker's yease valyl-trna synthetase have been purified to apparent homogeneity by classical methods. it was demonstrated that one of the two forms of the enzyme originates from the other by proteolysis, the respective amounts of each form depending on the physiological state of the yeast. the species mainly isolated from exponential growing yeast cells is a monomer of 130,000 daltons molecular weight. in stationary phase cells or in commercial yeast the major species is a degraded m ... | 1975 | 4150 |
| production, purification and characterization of thermomycolase, the extracellular serine protease of the thermophilic fungus malbranchea pulchella var. sulfurea. | the thermophilic fungus malbranchea pulchella produces a single extracellular, alkaline, serine protease when grown at 45 degrees c, on 2% casein as sole carbon source. the growth-associated production of protease in submerged cultures was inhibited by addition of glucose, amino acids, or yeast extract. a simple four-step purification which yields homogeneous protease in 78% yield is described. the protease has an isoelectric point of 6.0, a ph optimum of 8.5, and is completely inhibited by seri ... | 1976 | 4209 |
| beta-glucanases in the yeast cryptococcus albidus var. aerius. production and separation of beta-glucanases in asynchronous cultures. | beta-glucanases were detected in cell-free extracts of the yeast cryptococcus albidus var. aerius when grown on glucose as the sole carbon source. the production of beta-glucanases was followed in log-phase cells and stationary-phase cells; the maximal production of beta-(1 leads to 3) and beta-(1 leads to 6) glucanases takes place respectively in log-phase and stationary-phase cells. the results show that there are marked differences in the elution profiles on sephadex g-50 of fractions contain ... | 1976 | 4213 |
| a quantitative model for partition in aqueous multiphase systems. | a model for the partition of charged molecules in aqueous multiphase systems has been developed. the partition coefficient of one component, or the overall partition coefficient of a number of components, between two arbitrary phases is expressed in terms of the difference in electrical potential between the phases (due to electrolytes present in the system), the net charges of the partitioned components and their partition coefficients in a (sometimes hypothetical) uncharged state. the fraction ... | 1976 | 4308 |
| lysis of yeast cell walls. lytic beta-(1 leads to 6)-glucanase from bacillus circulans wl-12. | when grown in a mineral medium with yeast cell walls or yeast glucan as the sole carbon source, bacillus circulans wl-12 produces wall-lytic enzymes in addition to non-lytic beta-(1 leads to 3) and beta-(1 leads to 6)-glucananases. the lytic enzymes were isolated from the culture liquid by adsorption on insoluble yeast glucan in batch operation. after digestion of the glucan, the mixture of enzymes was chromatographed on hydroxylapatite on which the lytic activity could be resolved into one lyti ... | 1976 | 4309 |
| lysis of yeast cell walls. lytic beta-(1 leads to 3)-glucanases from bacillus circulans wl-12. | bacillus circulans wl-12 when grown in a mineral medium with yeast cell walls or yeast glucan as the soli carbon source, produced five beta-glucanases. two beta-(1 leads to 3)-glucanases (i and ii), which are lytic to yeast cell walls, were isolated from the culture liquid by batch adsorption on yeast glucan, and separated by chromatography on hydroxylapatite. lytic beta-(1 leads to 3)-glucanase i was further purified by carboxymethylcellulose chromatography. the specific activity of lytic beta- ... | 1976 | 4310 |
| nuclear-magnetic-resonance study of the active-site structure of yeast phosphoglycerate kinase. | the enzyme 3-phosphoglycerate kinase from yeast has been studied by observation of the proton nuclear magnetic resonance spectrum at 270 mhz using fourier transform techniques. difference spectroscopy was used to enhance the resolution and to identify specific ligand binding effects and conformational changes. perturbations involving single protons of amino-acid residues could thus be detected despite the relatively high molecular weight of the protein (47000), particularly in the aromatic (6-9 ... | 1976 | 4316 |
| 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 |
| control of inositol biosynthesis in saccharomyces cerevisiae: properties of a repressible enzyme system in extracts of wild-type (ino+) cells. | inositol biosynthesis was studied in soluble, cell extracts of a wild-type (ino) strain of saccharomyces cerevisiae. two reactions were detected: (i) conversion of d-glucose-6-phosphate to a phosphorylated form of inositol, presumably inositol-1-phosphate (ip synthethase, ec5.5.1.4), and (ii) conversion of phosphorylated inositol to inositol (ip phosphatase, ec3.1.3.25). the in vitro rate of conversion of glucose-6-phosphate to inositol was proportional to incubaion time and enzyme concentrati ... | 1976 | 4423 |
| ribonucleic acid synthesized in meiotic cells of saccharomyces cerevisiae: effect of culture medium ph. | pulse-labeled ribonucleic acid (rna) was extracted from polysomes of sporulating cells of saccharomyces cerevisiae and characterized in sucrose gradients and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. transfer rna, ribosomal rna, and heterodisperse rna, presumed to be messenger rna, were synthesized during a 20-min pulse at t4 and t6 when labeling was performed in sporulation medium adjusted to ph 6.0. furthermore, ribosomal rna was processed into functional ribosomes during t ... | 1976 | 4430 |
| development of microbodies in the yeast kloeckera growing on methanol. | a number of microbodies appear regularly in methanol-grown yeast cells, but rarely in ethanol- or glucose-grown cells. when one of representative methanol-utilizing yeasts, kloeckera sp.no. 2201 (also known as candida bodinii), was cultured on glucose and then transferred into a methanol medium, microbodies of small size could be observed in 2-h old cells. the number of microbodies per sectioned cell reached five to six after 4 h of cultivation. though the number of microbodies did not change du ... | 1976 | 4436 |
| chemical methods for the reduction of the purine content of baker's yeast, a form of single-cell protein. | | 1976 | 4651 |
| the structural subunit of glucose-6-phosphate dehydrogenase (baker's yeast). | the subunit molecular weight of glucose-6-phosphate dehydrogenase (g6pd) from baker's yeast has been evaluated. the subunit molecular weight value is shown to be 25,500 daltons by analytical ultracentrifugation, sds-polyacrylamide gel electrophoresis, and the number of peptides produced by cnbr cleavage. the number of nadp binding sites was determined to be one per 25,500 dalton unit. | 1975 | 4847 |
| benorylate interaction with indomethacin and phenylbutazone. | the simlutaneous oral administration of benorylate (4-(acetamido) phenyl 2-acetoxybenzoate) with either indomethacin or phenylbutazone to rats suffering from freund's adjuvant-induced arthritis leads to an anti-inflammatory effect which is significantly greater than the effect of the same drugs administered alone. such an additive anti-inflammatory effect is not apparent when the metabolites of benorylate (paracetamol, acetylsalicylic acid) are administered with indomethacin or phenylbutazone. p ... | 1976 | 5064 |
| evidence for the gamma-glutamyl cycle in yeast. | | 1976 | 5076 |
| bakers' yeast uridine nucleosidase is a regulatory copper containing protein. | | 1976 | 5088 |
| glucose-6-phosphate dehydrogenase from brewers' yeast. the effects of ph and temperature on the steady-state kinetic parameters of the two-chain protein species. | a systematic study has been made of the ph- and temperature-dependency of the steady-state kinetic parameters of the stabilized two-subunit enzyme species of glucose-6-phosphate dehydrogenase, in the absence of superimposed association-dissociation reactions. the vmax(app) data obtained in several buffers between ph 5 and 10 and at 18-32 degrees c lead to the postulate that at least two sets of protonic equilibria may govern the catalysis (one near ph 5.7 at 25 degrees c and another near ph 9.2) ... | 1976 | 5121 |
| yeast aminopeptidase i. chemical composition and catalytic properties. | an aminopeptidase (alpha-aminoacyl l-peptide hydrolase, ec 3.4.11.1) was purified to homogeneity from autolysates of brewer's yeast. the enzyme which is responsible for most of the yeast cell's aminopeptidase activity is a glycoprotein containing about 12% of conjugated carbohydrate and 0.02% zn2+ and having a complex quaternary structure. the active species has a molecular weight of approx. 600000 and an isoelectric point of 4.7. the enzyme is remarkably stable, even in dilute solutions. all ty ... | 1976 | 5147 |
| fluoride inhibition of inorganic pyrophosphatase. i. kinetic studies in a mg2+-ppi system using a new continuous enzyme assay. | reversible inhibition of bakers' yeast inorganic pyrophosphatase (ec 3.6.1.1) by fluoride has been studied as a function of substrate, metal-ion activator and inhibitor concentrations and ph using a new continuous enzyme assay with an automatic phosphate analyzer. the inhibition was shown to be the result of tight binding of fluoride by two catalytically active enzyme-substrate complexes. the reaction between pyrophosphatase and fluoride is relatively slow, so that the rate constants for the bin ... | 1976 | 5150 |
| further confirmation of carboxypeptidase y as a metal-free enzyme having a reactive serine residue. | the metal content of carboxypeptidase y was analyzed by the atomic absorption method. after exhaustive dialysis against an edta solution, the enzyme showed no loss of activity nor any significant content of metals (zh,mg,ca,cu,mn,ni,fe, and co). the activity was, however, rather sensitive to preincubation with various metals. the reactivity of a serine residue of the enzyme was also reevaluated. diisopropyl fluorophosphate (dfp) and phenylmethanesulfonyl fluoride (pmsf) stoichiometrically and ir ... | 1975 | 5404 |
| kinetic studies of carboxypeptidase y. iii. action on ester, amide, and anilide substrates and the effects of some environmental factors. | kinetic parameters of carboxypeptidase y are given for the hydrolyses of ester, amide, and anilide substrates. the kcat/km values were compatible with those of chymotrypsin ec 3.4.21.1 with a few exceptions. one ionizable group with a pk of around 5.8 was suggested to be involved in the free enzyme in hydrolyzing all the substrates, including peptide substrates. in addition, hydroxylaminolysis and the kinetic isotope effects of deuterium oxide indicated, with some reservations, a reaction mechan ... | 1975 | 5415 |
| study on proteins from yeast cytoplasmic ribosomes by two-dimensional gel electrophoresis. | proteins of yeast cytoplasmic ribosomes were analyzed by two different methods of two dimensional gel electrophoresis: run at ph 8.6 in 1-d1 and at ph 4.6 in 2-d (method a); run at ph 5.0 in 1-d and in the presence of sodium dodecyl sulfate in 2-d (method b). the numbers of proteins estimated were 28 (method a) and 29 or 30 (method b) in the 40s small subunit, and 40 (method a) and 41 (method b) in the 60s large subunit, respectively. molecular weights of proteins in the small and the large subu ... | 1976 | 5666 |
| effect of excision of the y-base on the interaction of trnaphe (yeast) with phenylalanyl-trna synthetase (yeast). | the interaction between trnaphe (yeast), from which the y-base has been removed by acid treatment, and phenylalanyl-trna synthetase (yeast) has been investigated by fluorescence competition titrations and sedimentation velocity runs. the binding parameters are given under various ionic conditions. the trnaphe-y still can occupy the specific binding sites on the enzyme. compared to unmodified trnaphe, the binding constant is lowered by more than one order of magnitude. it can be concluded that th ... | 1976 | 5707 |
| properties of hydroxysteroid oxidoreductase isolated from yeast. | yeasts can advantageously be utilized for the production of the 17beta-hydroxy-derivative, from 3-methoxy-8,14-seco-1,3,5(10),9(11)-estratetraene-14,17-dione (14,17-dione) while 14alpha-hydroxy and 14alpha,17beta-dihydroxy-derivatives are also formed. the biochemical properties of yeasts' enzymes responsible for the formation of the two monohydroxy-derivatives have been studied in detail. in the cell-free extract of saccharomyces the presence of two hydroxysteroid oxidoreductases could be detect ... | 1975 | 5855 |
| biosynthesis of yeast mannan. diversity of mannosyltransferases in the mannan-synthesizing enzyme system from yeast. | 1. a microsomal enzyme preparation from the yeast saccharomyces cerevisiae catalyzes the transfer of mannosyl units from gdpmannose to mannose and a number of mannose-containing oligosaccharides and glycosides whereby different glycosidic bonds are formed. 2. of the compounds tested besides mannose, only those containing an alpha-linked mannosyl unit at the nonreducing position of their molecule were effective as acceptors. monodeoxyanalogues of mannose as well as alpha-mannose phosphates did no ... | 1976 | 6052 |
| regulation of 6-hydroxy-2,4,5-triaminopyrimidine synthesis by riboflavin and iron in riboflavin-deficient mutants of pichia guilliermondii yeast. | the effect of riboflavin and iron on 6-hydroxy-2,4,5-triaminopyrimidine synthesis rate was investigated in the cultures of the yeast pichia guilliermondii (rib2 mutants) with the blocked second reaction to flavinogenesis. it was shown that riboflavin inhibited the 6-hydroxy-2,4,5-triaminopyrimidine synthesis rate in iron-rich and iron-deficient cells of mutants with low riboflavin requirements. cycloheximide did not prevent the stimulation of 6-hydroxy-2,4,5-triaminopyrimidine synthesis caused b ... | 1976 | 6053 |
| a nonspecific inhibitory effect of trna on the activity of 3-deoxy-d-arabino-heptulosonate-7-phosphate synthase from saccharomyces cerevisiae. | the inhibitory effect of trna on yeast 3-deoxy-d-arabino-heptulosonate-7-phosphate (dahp) synthase (ec 4.1.2.15) has been reinvestigated. from earlier studies the inhibition by trnaphe appeared to be quite specific. this study shows that trnaphe is indeed a potent inhibitor but so is unfractionated trna, as well as ribosomal rna and heparin. complete digestion to mononucleotides relieves the inhibition. since the enzyme requires a metal ion (co2+) we suggest that the rna and heparin are inhibito ... | 1976 | 6062 |
| regulation of fodder yeast candida tropicalis glutamine synthetase activity by the end products of glutamine metabolism. | effect of different products of glutamine metabolism on the activity of glutamine synthetase in the presence of mg2+, and mn2+ and co2+ as cofactors is studied. all the metabolites studied are found to inhibit the glutamine synthetase activity in the presence of any cation listed. the degree and the character of the inhibition by one or other metabolite depended in a considerable degree on the nature of the cation presented in the reaction mixture (mg2+, mn2+ or co2+). the mechanism of the cumul ... | 1976 | 6072 |
| purification and properties of the riboflavin kinase of the yeast pichia guilliermondii. | riboflavin kinase (e.c.2.7.1.26) was isolated from the cells of the yeast pichia guilliermondii. the enzyme was 680-fold purified uzing ammonium sulphate fractionation, chromatography on deae-sephadex a-50 and cm-sephadex c-50 and gel-filtration through sephadex g-75. purified enzyme preparation was free from phosphatases and fad-synthetase. the ph optimum was 8,7, the temperature optimum-45 degrees c. the enzyme was activated by zn2+, mg2+ and co2+ ions. km for riboflavin was 1,0x10(-5) m, for ... | 1976 | 6079 |
| modified 5'-nucleotides resistant to 5'-nucleotidase: isolation of 3-(3-amino-3-carboxypropyl) uridine 5'-phosphate and n2, n2-dimethylguanosine 5'-phosphate from snake venom hydrolysates of transfer rna. | a procedure for the quantitative measurement of the o2'-methylnucleoside constitutents of rna has recently been developed in this laboratory (gray, m.w. can. j. biochem. 53, 735-746 (1975)). this assay method is based on the resistance of o2'-methylnucleoside 5'-phosphates (pnm) (generated by phosphodiesterase hydrolysis of rna) to subsequent dephosphorylation by venom 5'-nucleotidase (ec 3.1.3.5). in the present investigation, two base-modified 5'-nucleotides, each displaying an unusual resista ... | 1976 | 6133 |
| kinetic effect of some aliphatic amines on yeast alcohol dehydrogenase. | initial rate studies of ethanol oxidation catalyzed by yeast alcohol dehydrogenase (ec 1.1.1.1) were carried out in the presence of varying concentrations of aliphatic amines over the ph range from 8.0 to 10.5. aliphatic amines either activate or inhibit the enzyme depending on whether the ph is greater or less than 9.5 suggesting that the protonated amines activate and the nonprotonated amines inhibit the enzyme. aliphatic amines activate yeast alcohol dehydrogenase by decreasing kb while they ... | 1976 | 6134 |
| regulation of acetyl-coa synthetase of saccharomyces cerevisiae. | acetyl-coenzyme a synthetase (ec 6.2.1.1) activity of saccharomyces cerevisiae was determined by a radioactive assay procedure. the activity in vitro was inhibited significantly by nadph, nadh, or amp and to a lesser extent by nadp, nad, or adp. glutamic acid and alpha-ketoglutaric acid were not inhibitory. the enzyme level was repressed when the cells were grown in a complex nutrient medium as opposed to the minimal medium. however, a glutamic acid auxotroph glul, when grown in excess glutamic ... | 1976 | 6141 |
| two forms of serine transhydroxymethylase, one absent in a thymidylate-less mutant in saccharomyces cerevisiae. | | 1976 | 6271 |
| alcohol oxidases of kloeckera sp. and hansenula polymorpha. catalytic properties and subunit structures. | 1. alcohol oxidase (alcohol: oxygen oxidoreductase) of a thermophilic methanol-utilizing yeast, hansenula polymorpha dl-1, was isolated in crystalline form. 2. this alcohol oxidase of h. polymorpha was more stable to heat than was the enzyme of kloeckera sp. this difference in heat stability is compatible with the difference in growth temperatures for both yeasts. 3. the crystalline alcohol oxidases of both yeast oxidized the lower primary alcohols (c-2 to c-4) as well as methanol. the apparent ... | 1976 | 6273 |
| studies on the active site of yeast hexokinase. specific phosphorylation of a serine residue induced by d-xylose and atpmg. | yeast hexokinase a(atp:d-hexose 6-phosphotransferase) is inactivated when incubated in the presence of xylose and atpmg, or in the presence of d-lyxose in a reaction medium in which atpmg is being continuously regenerated (phosphoenolpyruvate and pyruvate kinase). the inactivation is due to the phorphorylation of the protein. a linear relationship was observed between the inactivation and the incorporation of 32p from gamma-32p atp. all hexokinase and atpase activity of the enzyme is lost when o ... | 1976 | 6282 |
| the transport of s-adenosyl-l-methionine in isolated yeast vacuoles and spheroplasts. | 1. the properties of s-adenosyl-l-methionine accumulating system for both vacuoles and spheroplasts are described. yeast vacuoles were obtained by a modified metabolic lysis procedure from spheroplasts of saccharomyces cerevisiae. 2. isolated vacuoles accumulate s-adenosyl-l-methionine by means of a highly specific transport system as indicated by competition experiments with structural analogs of s-adenosyl-l-methionine. the s-adenosyl-l-methionine transport system shows saturation kinetics wit ... | 1976 | 6283 |
| influence of ph on the rate of ribosomal ribonucleic acid synthesis during sporulation in saccharomyces cerevisiae. | the rate of synthesis of ribosomal rna (rrna) is much slower during sporulation than during vegetative growth of yeast. if sporulating cells are transferred from normal incubation conditions at ph 8.8 to the same medium adjusted to ph 7.0, the rate of rrna synthesis increased to approach that observed in vegetative cells. the response to the ph change is quite rapid, occurring within 10 min. the ph-dependent, rate-limiting step appears to be in the processing of 35s ribosomal precursor rna to th ... | 1976 | 6427 |
| trinitrophenylation of nucleic acids and their constituents. | 1. under relatively mild conditions, nucleic acids and their constituents were trinitrophenylated with 2,4,6-trinitrobenzenesulfonate (tnbs) in aqueous solution (ph 8-11), yielding reddish-orange trinitrophenyl (tnp) derivatives. guanine residues were trinitrophenylated on the base residues at the 2-amino group (n2-tnp derivatives), and in addition, 2'- and 3'-hydroxyl groups of the ribose moieties of nucleosides or nucleotides were trinitrophenylated to form meisenheimer complexes. 2. the prepa ... | 1975 | 6442 |
| transport of riboflavin into yeast cells. | riboflavin-requiring mutants of saccharomyces cerevisiae are able to transport 14c-labeled riboflavin into the cell, although no significant transport is seen in commercial yeast or in the parent strain from which the mutants were derived. transport activity is greatest in the early to mid-log phase of anaerobic growth and declines sharply in the late log phase. in aerobically grown cells activity is substantially lower at all stages of growth. in the assay devised for its measurement, transport ... | 1976 | 6447 |
| the activating system of chitin synthetase from saccharomyces cerevisiae. purification and properties of the activating factor. | the yeast proteinase that causes activation of the chitin synthetase zymogen has been purified by a procedure that includes affinity chromatography on an agarose column to which the proteinaceous inhibitor of the enzyme had been covalently attached. the purified enzyme yielded a single band upon disc gel electrophoresis at ph 4.5 in the presence of urea. at the same ph, but without urea, a faint band was detected in coincidence with enzymatic activity, whereas at ph 9.5, either in the absence or ... | 1976 | 6452 |
| yeast alpha-isopropylmalate isomerase. factors affecting stability and enzyme activity. | yeast alpha-isopropylmalate isomerase was found to be markedly stabilized by high concentrations of glycerol and (nh4)2so4. such conditions of high ionic strength inhibited the enzyme, stabilized the enzyme to heat, and affected kinetic parameters. the isomerase was found to exhibit ionic strength-dependent hysteresis when enzyme, totally but reversibly inhibited by storage under conditions of high ionic strength of (nh4)2so4, was transferred to a lower concentration of (nh4)2so4. alpha-isopropy ... | 1976 | 6456 |
| the enzymic conversion of protoporphyrinogen ix to protoporphyrin ix in mammalian mitochondria. | protoporphyrinogen oxidase, an enzyme which catalyzes the oxidation of protoporphyrinogen ix to protoporphyrin ix in yeast cells, has been found in several mammalian tissues. it has been extracted from rat liver mitochondria by sonication in the presence of salt and detergent and partially purified. the enzyme is similar in many respects to yeast protoporphyrinogen oxidase. based on its behavior on sephadex g-200 the molecular weight of the enzyme is approximately 35,000. catalysis by protoporph ... | 1976 | 6461 |
| the production and growth characteristics of yeast and mycelial forms of candida albicans in continuous culture. | the growth characteristics of candida albicans cm145,348 have been examined under aerobic conditions in continuous culture. at different steady states the environment was controlled with respect to the concentrations of dissolved oxygen, carbon and nitrogen, the ph, and the temperature. dry matter, substrate concentration, yield, specific oxygen uptake, specific carbon dioxide release and respiration quotient were examined as a function of the dilution rate. the morphology depended on the carbon ... | 1976 | 6622 |
| yeast cell wall-dissolving enzymes of the thermotolerant actinomycete thermoactinomyces vulgaris. | the thermotolerant culture of thermoactinomyces vulgaris pa ii-4a was cultivated in the biotec fermenter to obtain the enzyme preparation with a high proteolytic and lytic activity. resistance of the cells of candida utilis and saccharomyces fragilis (mesophilic and thermotolerant strains) to the lytic action of the enzyme preparation was different. preliminary treatment of the yeast cells by l-cysteine increased their susceptibility to the lytic action of the preparation. the degree of lysis of ... | 1976 | 6860 |