| trends and innovations in rumen microbiology. | | 1976 | 5779 |
| equilibrium protection studies of the interaction of bovine glutamate dehydrogenase with purine nucleotide effectors. | | 1975 | 5298 |
| monovalent cation penetration into synaptic membranes. | | 1975 | 5301 |
| reversible uncoupling of the copper and cobalt spin systems in cobalt bovine superoxide dismutase at low ph. | | 1975 | 5307 |
| the interrelationship between the inhibitory activity of milk with different types of beta-lactoglobulins and the resistance of cattle to mastitis. | in the course of the investigation of piebald (black-white) cattle it is found that 17,62% animals produce the aa type beta-lactoglobulin, 49,52%--the ab type and 32,86%--the bb type. the higher inhibitory activity of milk with the bb type beta-lactoglobulin was found which retained in dilution 1 : 32. the total flora of teat, cyst and parenchyma milk of animals with the bb type beta-lactoglobulin as well as enterococcus bacteria were much lower than in milk of cows with the aa type homogenous f ... | 1975 | 5340 |
| nonspecific bactericidal activity of the lactoperoxidases-thiocyanate-hydrogen peroxide system of milk against escherichia coli and some gram-negative pathogens. | two strains of escherichia coli and one strain each of salmonella typhimurium and pseudomonas aeruginosa were killed by the bactericidal activity of the lactoperoxidase-thiocyanate-hydrogen peroxide system in milk and in a synthetic medium. h2o2 was supplied exogenously by glucose oxidase, and glucose was produced at a level which was itself noninhibitory. two phases were distinguished: the first phase was dependent on the oxidation of scn(-) by lactoperoxidase and h2o2, which was reversed by re ... | 1976 | 5374 |
| studies on d-tetrose metabolism. vi. crystallization and some properties of d-erythrulose reducatase from beef liver. | d-erythrulose reductase of beef liver was crystallized from ammonium sulfate solution at ph 8.17. the crystals are needle-shaped. the enzyme protein contains 851 amino acid residues per mole of the enzyme: lys28, his11, arg52, asp79, thr58, ser56, glu68, pro20, gly80, ala107, val112, met24, ile31, leu88, tyr7, phe22, trp4, and cys4. the enzyme is inactivated by exposure to temperatures below 12degrees. the inactivation is accelerated by increasing the salt concentration and decreasing the enzyme ... | 1975 | 5410 |
| kinetic study of the action of snake venom phospholipase a2 on human serum high density lipoprotein 3. | the hydrolysis of the phospholipids of intact human serum high density lipoprotein 3 (hdl3) by pure alpha-phospholipase a2 from crotalus adamanteus was studied by ph-stat titration. the enzyme quantitatively hydrolyzed phosphatidylcholine and phosphatidylethanolamine and left sphinogomyelin intact, yielding a stable and water-soluble modified hdl. lysophospholipids and free fatty acids, the products of hydrolysis, remained in the lipoprotein. when 1 mol of defatted bovine serum albumin/mol of su ... | 1976 | 5436 |
| subcellular structure of bovine thyroid gland. a study on bovine thyroid membranes by buoyant-density-gradient centrifugation in a b-xiv zonal rotor. | a combined mitochondrial and light mitochondrial fraction and a microsomal fraction were isolated from bovine thyroid gland and fractionated further in a b-xiv zonal rotor. a density gradient ranging from 20 to 50% (w/w) sucrose was used. the rotor was operated for 3 h at 45 000 rev./min. all manipulations were performed at 4 degrees c and at ph 7.4. 2. membranous material was recovered in two zones: zone i, containing microsomal material derived from both smooth endoplasmic reticulum and plasma ... | 1975 | 5997 |
| comparative study of the optimum ph value of serum alkaline phosphatase in various species of farm animals. | investigations were carried out on the alkaline phosphatase in the sera of cattle, horses, pigs, sheep, goats, and chickens, the ph value of the buffer used being 9.0-9.8-10.0-10.2-10.6 and 11.0, and the method applied--that of richterich. the ph value at which the serum alkaline phosphatase in the various farm animals and birds was most active was found to vary to a large extent. optimal values for the enzyme's activity usually range as follows: cattle, 10.2; pigs and goats, 10.0; sheep,--10.2; ... | 1975 | 5802 |
| beta-lactoglobulin ab fluorescence under different physico-chemical conditions. denaturation by urea and organic solvents. | dependences of different fluorescence parameters of bovine beta-lactoglobulin ab on the concentrations of urea (ph 2.8-8.8), ethanol (ph 2.1-10.2), and dioxane (ph 5.3) have been investigated. the denaturation properties (the free energy and the stoichiometry of denaturative interaction) are highly dependent on ph values. the data obtained indicate that the hydrophobic interactions are the determining forces in the stabilization process of the beta-lactoglobulin molecule. the relative contributi ... | 1975 | 6900 |
| inhibition of bovine hepatic fructose-1,6-diphosphatase by substrate analogs. | purified bovine hepatic fructose-1,6-diphosphatase, which exhibits maximal activity at neutral ph, is competitively inhibited by several analogs of its substrate, fructose 1,6-diphosphate. these include glucose 1,6-diphosphate (ki = 9.4 x 10(-5) m), hexitol 1,6-diphosphate (ki = 2.3 x 10(-4) m), and 2,5-anhydro-d-mannitol 1,6-diphosphate (ki = 3.3 x 10(-8) m), and 2,5-anhydro-d-glucitol 1,6-diphosphate (ki = 5.5 x 10(-7) m). the ki values for both 2,5-anhydro-d-mannitol 1,6-diphosphate and 2,5-a ... | 1976 | 5447 |
| bovine spleen cathepsin b1 and collagenolytic cathepsin. a comparative study of the properties of the two enzymes in the degradation of native collagen. | bovine spleen cathepsin b1 and collagenolytic cathepsin were separated by chromatography on amberlite irc-50 and collagenolytic cathepsin was partially purified by chromatography on deae-sephadex (a-50). 2. collagenolytic cathepsin degraded insoluble tendon collagen maximally at ph 3.5 and 28 degrees c; mainly alpha-chain components were released into solution. at 28 degrees c the telopeptides in soluble skin collagen were also cleaved to yield alpha-chain components. collagenolytic cathepsin wa ... | 1976 | 6003 |
| inhibition of the self-assembly of tubulin by diethylpyrocarbonate and photooxidation. | | 1976 | 6033 |
| complete tyrosine assignments in the high-field 1h nuclear magnetic resonance spectrum of bovine pancreatic trypsin inhibitor selectively reduced and carboxamidomethylated at cystine 14-38. | the low-field portions of the 250-mhz 1h nuclear magnetic resonance spectra of native and chemically modified basic pancreatic trypsin inhibitor have been studied as a function of ph over the range ph 5-13. in derivatives selectively reduced and carboxamidomethylated at cystine 14-38, resonances associated with 15 of the 16 protons of the aromatic rings of the four tyrosines of the inhibitor have been located and assigned to specific tyrosyl residues. titrations of ph yielded pk's for tyrosines ... | 1976 | 6043 |
| lipid-protein interactions in membrane models. fluorescence polarization study of cytochrome b5-phospholipids complexes. | according to previous authors, cytochrome b5, when extracted from bovine liver by a detergent method, is called cytochrome d-b5. on the other hand, the protein obtained after trypsin action, which eliminates an hydrophobic peptide of about 54 residues, is called cytochrome t-b5. fluorescence polarization of the dansyl phosphatidylethanolamine probe inserted into phospholipid vesicles is very sensitive to the binding of proteins, and so is a useful method to study lipid-protein interactions. the ... | 1976 | 6065 |
| isolation of mitochondrial dna, purified of nuclear dna, from animal tissues (degree of methylation and level of pyrimidine nucleotide clustering--criteria of purity). | a method of preparation of mitochondria free of nuclear dna and its fragments by treatment of mitochondria with deae-cellulose has been developed. this method is based on binding nuclear nucleic acids and nucleoproteins to deae-cellulose particles in the media used for isolation of mitochondria. treatment with deae-cellulose under the conditions described does not induce any visible degradation of mitochondria and mitochondrial dna. the mitochondrial dna preparations obtained from beef and rat l ... | 1976 | 6074 |
| catalytic properties of alpha-ketoglutarate decarboxylase from bovine brain. | investigation of the effect of different buffer systems on the rate of alpha-ketoglutarate decarboxylase reaction have shown that the ph optimum is 6.8 in tris-maleic, tris-h3po4 and kh2po4-koh buffers, and it is 7.5 in imidazole buffer. the highest reaction rate was observed when using phosphate containing buffers. the increase of phosphate concentration increased considerably the rate of alpha-ketoglutarate decarboxylase reaction. mg2+ and ca2+ were shown to affect slightly the reaction rate. ... | 1976 | 6080 |
| serine transhydroxymethylase: mechanism of aldolase activation by folate. | | 1976 | 7202 |
| mg2+ and the permeability of heart mitochondria to monovalent cations. | | 1976 | 7203 |
| cation-binding property of choroid plexus peptide iif. | preparations of the melanotropic-lipolytic peptide iif from bovine choroid plexus contain 3% ca, 1% mg and less than 0.1% na and k. ca and mg were removed by gel filtration on sephadex g-10 in 1 n acetic acid. capacity of the resulting cation-free peptide to bind ca++, mg++, na+ and k+ was examined with the method of hummel and dreyer (biochim. biophys. acta 63: 530-532, 1962). peptide iif bound a maximum of 3.7 to 4.4 meq of ca++, mg++, na+ or k+ per g of peptide. for each cation, linear scatch ... | 1976 | 5598 |
| changes in the electric dipole vector of human serum albumin due to complexing with fatty acids. | the magnitude of the electric dipole vector of human serum albumin, as measured by the dielectric increment of the isoionic solution, is found to be a sensitive, monotonic indicator of the number of moles (up to at least 5) of long chain fatty acid complexed. the sensitivity is about three times as great as it is in bovine albumin. new methods of analysis of the frequency dispersion of the dielectric constant were developed to ascertain if molecular shape changes also accompany the complexing wi ... | 1976 | 6087 |
| beta-galactosidase from bacillus stearothermophilus. | several strains of thermophilic aerobic spore-forming bacilli synthesize beta-galactosidase (ec 3.2.1.23) constitutively. the constitutivity is apparently not the result of a temperature-sensitive repressor. the beta-galactosidase from one strain, investigated in cell-free extracts, has a ph optimum between 6.0 and 6.4 and a very sharp ph dependence on the acid side of its optimum. the optimum temperature for this enzyme is 65 degrees c and the arrhenius activation energy is about 24 kcal/mol be ... | 1976 | 6142 |
| age related variations in plasma electrolytes of hereford cattle under range conditions. | | 1976 | 5228 |
| biochemical characterization of an avian spermatozoan acrosin and comparison of its properties to those of bovine trypsin and mammalian acrosins. | | 1976 | 6190 |
| purification and partial kinetic characterization of l-glutamate dehydrogenase from bovine adrenal gland mitochondria. | | 1976 | 6264 |
| cobalt bovine superoxide dismutase. reactivity of the cobalt chromophore in the copper-containing and in the copper-free enzyme. | 1. the reactivity of the zinc site of bovine superoxide dismutase has been probed by observing optical and electron paramagnetic resonance changes, under several conditions, of the co(ii)-substituted protein. 2. only in the absence of copper are the optical and electron paramagnetic resonance spectra of the cobalt chromophore appreciably affected by alkaline ph or by cyanide. with both reagents the reaction with the copper-containing protein appears to involve the water molecule bound to the cop ... | 1976 | 6275 |
| properties of prostaglandin synthetase of rabbit kidney medulla. | the formation in vitro of prostaglandins e2, d2, and f2alpha from arachidonic acid by rabbit kidney medulla homogenate or microsomal fraction is markedly affected by the composition of the incubation medium employed. optimal biosynthesis is obtained in 0.1 m potassium phosphate buffer, with the optimum ph being 8.0--8.8. under these conditions prostaglandin formation is linear up to arachidonic acid concentration of 30 mum. the initial rate of formation of prostaglandin e2 + prostaglandin d2 is ... | 1976 | 6277 |
| calf-spleen nicotinamide--adenine dinucleotide glycohydrolase. solubilization purification and properties of the enzyme. | nad glycohydrolase of calf spleen was solubilized with pancreatic lipase and purified approximatively 800-fold to a specific activity of 7 units/mg of protein by successive deae-cellulose and carboxymethyl-cellulose chromatography. the purified enzyme has a molecular weight of 24,000 and is characterized by a double band on disc gel electrophoresis. some kinetic properties of the nad-glycohydrolase-catalyzed hydrolsis of nad have been examined using a titrimetric assay for enzyme activity. the r ... | 1976 | 6279 |
| regulation of secretion from the adrenal medulla. evidence for adenylate cyclase activity in secretory vesicle membranes. | adenylate cyclase activity has been found in purified secretory vesicle membranes from the adrenal medulla. activity was detected both by formation of radioactive camp from alpha-32patp and by the competitive protein binding assay for camp. activity was highest at ph 8.0 to 8.5, and was stimulated by sodium fluoride and gppnhp, a gtp analogue known to stimulate adenylate cyclase activity in plasma membrane preparations. the reaction rate was strongly dependent on the molar ratio of mg2+:atp in t ... | 1976 | 5442 |
| internal ph of isolated chromaffin vesicles. | the passive permeability of isolated chromaffin vesicles to h+ and the internal ph of the vesicles under various conditions were measured. potentiometric measurements of k+ and h+ fluxes in the presence of selected ionophores and uncouplers indicated that the membrane is highly impermeable to both protons and potassium. deltaph across the chromaffin granule membrane was measured by 14cmethylamine distribution. at ph 6.85, the deltaph was 1.16 with the intravesicular space being found acidic. var ... | 1976 | 5444 |
| radioreceptor assay of acth. | | 1976 | 6809 |
| mechanisms and regulation of biosynthesis of saturated fatty acids. | | 1976 | 6981 |
| subsynaptosomal distribution, inhibition, and characterization of the binding of (14c) 5-oh-indole-3-acetaldehyde to brain preparations. | the distribution of the monoamine oxidase (mao) dependent binding of 14c serotonin as well as of pre-formed 14c 5-oh-indole-3-acetaldehyde to synaptic subfractions paralleled the gross distribution of mao. the binding of 14c serotonin and mao activity in brain preparations was inhibited by cns antidepressants (imipramine) or stimulants (caffeine), by hallucinogens (n,n-dimethyltryptamine), sedatives (chlorpromazine), and other drugs. the protein-lipid nature of the binding macromolecule was dete ... | 1976 | 7005 |
| values of acid-base equilibrium in the blood of various species of domestic animals. | by means of the astrup equilibration method the values of the acid-base balance of the blood were determined in 104 cows, 99 horses, 100 pigs, 15 sheep, 20 goats, and in 101 dogs. the ph values of the blood, the partial pressure of co2, the base excess, the base buffer, the standard bicarbonate, the actual bicarbonate, and the total co2 were processed statistically and are presented in tables. | 1976 | 7040 |
| species and phenobarbitone-induced differences in the kinetic constants of liver microsomal harmine o-demethylation. | 1. the apparent kinetic constants for the o-demethylation of harmine to harmol by 10 000 g supernatant fractions from livers of mice, rats, guinea-pigs, rabbits, cats and cows have been determined. the km values were 10-39 mum and vmax 0-25 and 1-65 nmol/mg protein/min. 2. optimal conditions of incubation time and nadp requirements differed between species. in all species except cat and cow the rate of o-demethylation of harmine was linear for 5 min, but in the latter species was linear for 15 m ... | 1976 | 7043 |
| bovine liver glutamate dehydrogenase. | | 1976 | 7109 |
| contribution to the knowledge of swiss piroplasmas. | the authors identify 3 species of babesia, which parasitize cattle in switzerland (babesia major, b. divergens and b. hovis). they also confirm the presence of b. canis in a dog in the proximity of geneva. finally, for the first time in switzerland, they point out the presence of non-identified babesia in various rodents (apodemus sylvaticus, a. flavicollis and clethrionomys glareolus). | 1975 | 7111 |
| a new method using p-benzoquinone for coupling antigens and antibodies to marker substances. | a method using p-benzoquinone for coupling antigens and antibodies to enzymes and erythrocytes is described. the method involves the treatment of proteins (or polysaccharides) at ph 6 or 7 with an excess of p-benzoquinone. after removal of the unreacted reagent by gel filtration, the "activated" proteins were coupled at ph 8-9 with enzymes or erythrocytes. biological activities of the proteins were not substantially modified by this treatment since 80-100% of the antigen binding capacity was fou ... | 1976 | 7179 |
| phosphatidylinositol exchange protein. effects of membrane structure on activity and evidence for a ping-pong mechanism. | | 1976 | 7210 |
| purification and characterization of a purine-nucleoside phosphorylase from bovine thyroid. | | 1976 | 7211 |
| further evidence for the transmission of mansonella ozzardi by simulium amazonicum in brazil. | the transmission of mansonella ozzardi was studied in two rubber collecting villages on the river purus, state of amazonas, brazil. haematophagous insects were collected from human and bovine baits during the day and night: 687 mansonia amazonensis and 154 culicoides sp. indet. were free from infection with m. ozzardi. the former species is probably not a vector, but the low numbers of culicoides dissected preclude any determination of its vector status. thirty-five (0-99%) of 3530 simulium amaz ... | 1976 | 7215 |
| some properties of a microsomal oleate desaturase from leaves. | 1. when 1-14coleoyl-coa was incubated with a pea-leaf homogenate oleate was both incorporated into microsomal 3-sn-phosphatidylcholine and released as the unesterified fatty acid. the proportion of oleate incorporated into this phospholipid was dependent on the relative amounts of thiol ester and microsomal preparation present in reactions. 2. at the concentrations of microsomal preparation and 14coleoyl-coa used to study oleate desaturation the metabolism of the thiol ester was essentially comp ... | 1976 | 7242 |
| human cathepsin g. catalytic and immunological properties. | 1. the specificity of cathepsin g, a neutral proteinase from human spleen, was examined by use of low-molecular-weight substrates. the enzyme was found to hydrolyse several synthetic substrates also hydrolysed by chymotrypsin, but with different kinetic constants. 2. maximal activity against benzoyl-dl-phenylalanine 2-naphthol ester and azo-casein was in the range ph 7.5-8.0. 3. the sensitivity of cathepsin g to the action of potential inhibitors was determined, and compared with those of bovine ... | 1976 | 7245 |
| a ferrocyanide charge-transfer complex of bovine superoxide dismutase. relevance of the zinc imidazolate bond to the redox properties of the enzyme. | | 1976 | 7251 |
| regulation of adrenal tyrosine hydroxylase activity: neuronal versus local control studied with apomorphine. | | 1976 | 7260 |
| induction of a local transplant vs. host reaction by cells of the palatine tonsils. | | 1975 | 7889 |
| metabolic degradation of cartilage by leucocyte enzymes under the influence of antirheumatic drugs (author's transl). | lately the importance and participation of leucocytes in rheumatoid arthritis have been discussed. in order to study catabolic reactions in connective tissue we investigated the autolytic liberation of mucopolysaccharides in cartilage alone and in the presence of leucocyte enzymes. factors of optimal experimental conditions, such as ph and constituents of incubation medium, incubation time and the number of leucocytes, were determined. in further experiments we studied the influence of antirheum ... | 1976 | 7278 |
| activation of glutamate dehydrogenase by 3', 5'-cyclic adenosine monophosphate. | | 1975 | 6317 |
| cytochrome p-450 of bovine adrenal mitochondria. ligand binding to two forms resolved by epr spectroscopy. | the binding of cholest-5-ene-3beta,20alpha-diol (20alpha-hydroxycholesterol), 11-deoxycorticosterone, and aminoglutethimide to cytochrome p-450 in bovine adrenal mitochondria was measured by changes in optical spectra at room temperature and by epr spectra at 14 k. the two methods provided nearly identical quantitation of these interactions with cytochrome p-450. two distinct high spin forms of cytochrome p-450 were revealed by epr spectra. the predominant high spin species (g = 8.2) was decreas ... | 1976 | 6460 |
| adrenodoxin reductase. properties of the complexes of reduced enzyme with nadp+ and nadph. | anaerobic reduction of the flavoprotein adrenodoxin reductase with nadph yields a spectrum with long wavelength absorbance, 750 nm and higher. no epr signal is observed. this spectrum is produced by titration of oxidized adrenodoxin reductase with nadph, or of dithionite-reduced adrenodoxin reductase with nadp+. both titrations yield a sharp endpoint at 1 nadp(h) added per flavin. reduction with other reductants, including dithionite, excess nadh, and catalytic nadp+ with an nadph generating sys ... | 1976 | 6475 |
| effects of citrus pulp in high urea rations for steers. | effects of pelleted and conventional citrus pulp as a replacement for corn, with soybean meal added to keep protein comparable, were tested in rations with 5% urea and 33.33% sugarcane bagasse for fistulated steers. thus, all rations were low in readily fermented carbohydrates other than those of corn or citrus pulp. evaluation criteria were concentrations of urea in blood and of ph, ammonia, and volatile fatty acids of rumen fluid. citrus pulp for diets 1, 2, 3, and 4 was 0, 19, 38, or 55%. rum ... | 1976 | 6495 |
| pharmacological differences between the optical isomers of ibuprofen: evidence for metabolic inversion of the (-)-isomer. | | 1976 | 6706 |
| ca++ binding properties of human prothrombin. | the binding of ca++ to human prothrombin has been investigated by equilibrium dialysis. the protein exhibited a positive cooperativity phenomenon for the first three ca++ bound. eleven to twelve ca++ binding sites have been found. they could be differentiated in terms of two classes of sites with respect to their ca++ affinity: 5 strong binding sites (log kassoc = 3.9) and 7 weak binding sites (log kassoc = 2.9). we attempted to determine the hill coefficient of the strong binding sites responsi ... | 1976 | 7324 |
| cyclic nucleotides, protein phosphorylation and synaptic function. | | 1976 | 7379 |
| prolactin-releasing and release-inhibiting factor activities in the bovine, rat, and human pineal gland: in vitro and in vivo studies. | the effects of crude extracts of bovine, rat, and human pineal glands on prolactin (prl) release were studied using an in vitro system. in addition, the effects of a known pineal constituent, arginine vasotocin (avt), and crude bovine pineal extract (bpe) on prl secretion were studied in vivo. normal male rat hemipituitaries (hp), incubated with bpe (13 mg tissue/hp)released 200%, 150%, and 285% more prl into the medium than did their corresponding untreated control halves incubated in either me ... | 1976 | 7446 |
| adenylyl cyclase activities in ovarian tissues. i. homogenization and conditions of assay in graafian follicles and corpora lutea of rabbits, rats, and pigs: regulation by atp, and some comparative properties. | responsiveness of ovarian adenylyl cyclases to luteinizing hormone (lh), found to be 5 to 10-fold in cell-free preparations under optimal conditions, required gentle homogenizations and storage in sucrose-containing media. assay conditions required the use of an atp-regenerating system consisting of creatine kinase, creatine phosphate, and myokinase for the preservation of atp levels. lh-stimulated adenylyl cyclase (ac) in rabbit cl showed the following properties: 1) the ph optimum of basal act ... | 1976 | 7447 |
| studies on normal human bone marrow cultures in controlled environment thin-film culture systems. | two thin film culture systems, the controlled environment steady state system (ss) and the rocker tube configuration of that system (rt), were used to identify some of the conditions that appear to maintain morphologic and functional characteristics of cells of human bone marrow explants in vitro. the systems configuration assured continual gassing, control and easy monitoring of the cultures. cytocentrifuge preparations of media of specimens cultured in rt disclosed, though in decreasing number ... | 1976 | 7532 |
| the removal of non-collagen components from newborn calf dermis with magnesium chloride solution. | 1. non-collagenous substances in newborn calf dermis were extracted with solutions of various concentrations of mgcl2. the total protein and hydroxyproline contents in mgcl2 extracts increased with increase in the concentration of mgcl2 in the solutions. in particular, steep increases of their contents were observed at concentrations of mgcl2 from 0.5 to 1.0 m. total amounts of hydroxyproline in 1.0, 2.0, and 3.0 m mgcl2 extracts were equivalent to 40-50% of the hydroxyproline content in the who ... | 1976 | 7551 |
| regulation of the transmembrane potential of isolated chromaffin granules by atp, atp analogs, and external ph. | the transmembrane potential of isolated chromaffin granules has been measured using the permeant ions 14cmethylamine and 35sthiocyanate, as well as the fluorescent probe, 9-aminoacridine. at ph 7.0, the granule membrane had a nernst proton potential of -45mv, inside negative. this potential was sensitive to the external ph, but was unaffected by k+,na+, ca2+, mg2+, or other cations. the ph of zero potential was 6.25 for both methylamine and thiocyanate. thiocyanate also had a nernst potential of ... | 1976 | 7561 |
| distribution of enzyme activities in subcellular fractions of bovine retina. | centrifugation of homogenates of bovine retinas to isopycnic equilibrium in sucrose density gradients yielded three partially overlapping bands of particles which were, in the order of increasing density: (a) photoreceptor cell (rod) outer segments; (b) plasma membranes, lysosomes, and large fragments of endoplasmic reticulum; and (c) mitochondria. the only enzyme activity investigated which had a peak coinciding only with outer segment fractions was guanylate cyclase. enzyme activities with pea ... | 1976 | 7565 |
| milk lipoprotein lipases: a review. | lipoprotein lipase activity has been found in the milks from severals species where it is assumed to result from leakage from the mammary gland into milk. the function of the enzyme in the gland is apparently to assist in the transfer of blood lipoprotein triacylglycerol fatty acids into milk triacylglycerols. bovine skim milk is one of the richest sources of lipoprotein lipase and this enzyme has been purified extensively (7000 fold) by affinity chromatography. the lipase has a molecular weight ... | 1976 | 7579 |
| diet calcium and ph versus mineral balance in holstein cows 84 days pre- to 2 days postpartum. | sixteen dry holstein cows were assigned four groups combining either .2 or 2.1% calcium and ph of either 4.5 or 6.1 in a 2 x 2 factorial arrangement of treatments to study the effect of diet calcium and acidity (ph) on voluntary intake of dry matter, mineral metabolism, and blood constituents. the 86-day experiment was started 84 days prepartum and completed 2 days postpartum. voluntary dry matter ingestion tended to be higher with higher calcium and acidity (lower ph) diets. calcium nutriture w ... | 1976 | 7581 |
| a comparison of the effect of flurbiprofen on prostaglandin synthetase from human rheumatoid synovium and enzymatically active animal tissues. | | 1976 | 7661 |
| fibrinogen and fibrin monomer conformation changes dependent of ph magnitude. | conformational states of fibrinogen and fibrin monomer were studied by methods of differential and solvent-perturbation spectrophotometry and ultraviolet fluorescence at about neutral ph (6.5) and in the region of lower ph, 3.2 to 4.0. to prevent repolymerization of fibrin monomer at ph 6.5, urea was added in a non-denaturing concentration of 1.7 m. in the acid region specified, the immediate environment of tyrosine and tryptophan residues was found to be more polar and the accessibility to pert ... | 1976 | 7745 |
| purification and characterization of the two molecular forms of aspergillus oryzae acid protease. | the isolation and partial characterization of the acid proteases a1 and a2 (ec3.4.23.6) from aspergillus oryzae grown on solid bran culture are described. the purified preparations were essentially homogeneous by several criteria including sedimentation analysis and polyacrylamide gel electrophoresis. the physiochemical properties of the proteases a1 and a2 were as follows (in the order: a1, a2): molecular weight: 63 000 & 32 000; sedimentation coefficient s20, w: 3.93 and 3.16 s; diffusion cons ... | 1976 | 8138 |
| milk protein quantity and quality in low-birthweight infants: i. metabolic responses and effects on growth. | the optimal quantity and quality of protein for low-birthweight infants is undefined. in this study, 106 well, appropriate-for-gestational age, low-birthweight infants weighing 2,100 gm or less were grouped in three gestational age categories: t1 = 28 to 30 weeks; t2 = 31 to 33 weeks; t3 = 34 to 36 weeks. each group was assigned randomly to either banked human milk (bm) or to one of four isocaloric formulas varying in quantity and quality of protein but not in mineral content or in fat content: ... | 1976 | 7767 |
| the excretion of phylloerythrin and bilirubin by calves and sheep. | under general anaesthesia the common bile duct was ligated in two sheep and two calves. occlusion of the duct was permanent and was followed by portal fibrosis, proliferation of bile ducts and intrahepatic bile stasis. mild hepatic cell damage was accompanied by the release of glutamate dehydrogenase, sorbitol dehydrogenase and arginase into serum. the release of gamma-glutamyl transpeptidase was slower but more continuous. one sheep and one calf developed peritonitis associated with the leakage ... | 1976 | 7808 |
| incidence of arbovirus antibodies in bovine, ovine and human sera collected in eastern sicily. | the incidence of antibodies against 9 arboviruses in ovine, bovine and human sera collected in eastern sicily was studied. a high incidence of antibodies was found especially against bhanja virus in all sera and against sandfly fever sicilian in ovine sera only. the incidence was higher than that reported in 1971 for the western part of sicily. these findings suggest an increase in the circulation of arboviruses in this area; the causes are briefly discussed. | 1976 | 7946 |
| effect of chlorpromazine on tyrosine hydroxylase in rat brain striatum and beef adrenal medulla. | | 1976 | 7961 |
| n-(1-pyrene)maleimide: a fluorescent cross-linking reagent. | n-(1-pyrene)maleimide is nonfluorescent in aqueous solution but forms strongly fluorescent adducts with sulfhydryl groups of organic compounds or proteins. the conjugation reactions of n-(1-pyrene)maleimide are relatively fast and can be monitored by the increase in fluorescence intensity of the pyrene chromophore. in cases where primary amino groups are also present in the system, we have observed a red shift of the emission spectra of the fluorescent adducts subsequent to the initial conjugati ... | 1976 | 7290 |
| purification and properties of atpase inhibitor from rat liver mitochondria. | (1) the atpase inhibitior protein has been isolated from rat liver mitochondria in purified form. the molecular weight determined by sodium dodecyl sulfate gel electrophoresis is approximately 9500, and the isoelectric point is 8.9. (2) the protein inhibits both the soluble atpase and the particle-bound atpase from rat liver mitochondria. it also inhibits atpase activities of soluble f1, and inhibitor-depleted submitochondrial particles derived from bovine heart mitochondria. (3) on particle-bou ... | 1976 | 7295 |
| kinetics of the inactivation of trypsinogen by methanesulfonyl fluoride in the ph-stat. | | 1976 | 7969 |
| the effects of proteolytic digestion by trypsin on the structure and catalytic properties of reduced nicotinamide-adenine dinucleotide dehydrogenase from bovine heart mitochondria. | 1. at 21 degrees c incubation of nadh-ubiquinone-1 reductase (complex 1) with trypsin caused selective inhibition of nicotinamide nucleotide transhydrogenase activity. the reduction of k3fe(cn)6 by nadh or nadph was unaffected, but a slow decrease in the rate of reduction of ubiquinone-1 by nadh was observed. 2. the ph-dependence of nicotinamide nucleotide transhydrogenase activity differed in complex i and trypsin-treated complex i. the trypsin-labile activity had a ph optimum of approx. 6.5, w ... | 1976 | 8040 |
| human serum and synovial fluid hyaluronidase--bovine testicular hyaluronidase is not a valid substitute in drug evaluation studies. | | 1976 | 8044 |
| importance of sh groups in catalysis by bovine brain acid phosphatase. | the rate of inactivation of acid phosphatase (ec 3.1.3.2) from bovine brain by dithiobis-(2-nitrobenzoic acid) (nbs2) is identical to the rate of titration of one of the two sh groups of this enzyme. the rate of inactivation of the enzyme by nbs2 is ph dependent and, at 300 mm nacl, can be described by the reaction of a single sh group of pk 8.4. at low ionic strength the pk determined from the k inactivation vs. ph profile is 7.7 and the results deviate markedly from the predicted values at ph ... | 1976 | 7316 |
| guanylate cyclase. existence of different forms and their regulation by nucleotides in calf uterus. | the activity of calf uterus guanylate cyclase (ec 4.6.1.2) exists in at least two and most probably three distinct forms. the cytosolic enzyme exhibits hyperbolic substrate curves with respect to gtp and mn2+, while the particulate cyclases (nuclear and microsomal)display sigmoidal (gtp) and hyperbolic (mn2+) relationships. the hill coefficient for the gtp dependence is 0.9 for the cytosolic, 1.5 for the nuclear, and 1.4 for the microsomal enzyme. the cytosolic enzyme has a km for gtp of 70 mum ... | 1976 | 7317 |
| study of pyridine nucleotides in ocular tissues. iii. concentration of nad and nadh in the retina of various animals. | | 1975 | 8067 |
| energetics of primary processes in visula escitation: photocalorimetry of rhodopsin in rod outer segment membranes. | a sensitive technique for the direct calorimetric determination of the energetics of photochemical reactions under low levels of illumination, and its application to the study of primary processes in visula excitation, are described. enthlpies are reported for various steps in the bleaching of rhodopsin in intact rod outer segment membranes, together with the heats of appropriate model reactions. protonation changes are also determined calorimetrically by use of buffers with differing heats of p ... | 1976 | 8077 |
| histone interactions in solution and susceptibility to denaturation. | histone interactions in solution may depend upon treatments used for purification. optical rotatory dispersion and sedimentation-velocity measurements have been made in a reference solvent, before and after exposure to various treatments, to investigate histone susceptibility to irreversible denaturation. some acid conditions and urea and guanidine solutions may denature. interaction studies performed on nondenatured histones indicate that the dimer, (h4)(h3), and tetramer, (h4)2(h3)2, dissociat ... | 1976 | 8079 |
| properties of crystalline reduced nicotinamide adenine dinucleotide phosphate-adrenodoxin reductase from bovine adrenocortical mitochondria. ii. essential histidyl and cysteinyl residues at the nadph binding site of nadph-adrenodoxin reductase. | the binding site of nadph in nadph-adrenodoxin reductase was examined using crystalline enzyme from bovine adrenocortical mitochondria by studies on the effects of photooxidation and chemical modifications of amino acid residues in the reductase. (1) photoxication decreased the enzymatic activity of nadph-adrenodoxin reductase. photooxidation of the reductase was prevented by nadp+, adrenodoxin, or reduced glutathione, but not nad+. photoinactivation caused loss of a histidyl residue, but not of ... | 1976 | 8083 |
| ph dependence of the hydrolysis of hippuric acid esters by carboxypeptidase a. | the ph dependence (ph 4.5-10.5) of the hydrolysis of seven hippuric acid esters (c6h5conhch2c-o2cr1r2co2h: 1a: r1 = r2 = h; 1b: r1 = r2 = ch3; 1c: r1 = h, r2 = p-clc6h4; 1d: r1 = h, r2 = c2h5; 1e: r1 = h, r2 = (ch3)2chch2; 1f: r1 = h, r2 = c6h5; 1g: r1 = h, r2 = c6h5ch2) by bovine carboxypeptidase a has been investigated, and the ph dependence of the substrate activation of 1a-c and the substrate inhibition of 1d-g have been compared. for all seven esters the catalytically productive binding of ... | 1976 | 8087 |
| pulse fluorimetry study of beef liver glutamate dehydrogenase reduced nicotinamide adenine dinucleotide phosphate complexes. | single photon counting pulse fluorimetry has been used in order to study the two ternary complexes gdh-gtp-nadph and gdh-l-glutamate-nadph and the quaternary complex gdh-gtp-l-glutamate-nadph. the fluorescence decay of the enzyme-bound nadph is not monoexponential in any of these complexes. moreover, it does not seem to be dependent on the coenzyme concentration. the experimental curves can be satisfactorily fitted with the sum of two exponentials, the relative amplitudes of which significantly ... | 1976 | 8088 |
| oxidation of s-e-carboxymethyl-selenocysteine by l-aminoacid oxidase and by d-aspartate oxidase. | se-carboxymethyl-dl-selnocysteine (cmsec) has been prepared in a pure crystalline form from selenocysteine and monochloracetic acid. it has been shown that cmsec is a substrate for the l-aminoacid oxidase form snake venom and for the d-aspartate oxidase from beef kidney. oxygen consumption and ammonia production indicate that only the l or the d form of cmsec ar acted upon respectively by one or the other of the above enzymes. no noticeable differences were shown in the oxidation rate of cmsec a ... | 1976 | 8703 |
| stereospecificity of interaction of neuroleptic drugs with neurotransmitters and correlation with clinical potency. | | 1976 | 8733 |
| ph dependence of tritium exchange with the c-2 protons of the histidines in bovine trypsin. | at ph 8.9 and 37 degrees c the half-times for tritium exchange with the c-2 protons of the histidines of trypsin are 73 days for his-57, and greater than 1000 days for his-40 and his-91. these half-times are much longer than the half-life of exchange for the c-2 proton of free histidine (2.8 days at pd 8.2), and longer than any previously reported half-time of exchange at ph greater than 8. these very low rates of exchange are discussed with reference to the refined structure of trypsin. the tri ... | 1976 | 8090 |
| reinvestigation of the phenacyl bromide modification of alpha-chymotrypsin. | the modification of alpha-chymotrysin with phenacyl bromide has been reinvestigated over a wide ph range. evidence is presented that indicates that the nature of the phenacyl-modified enzymes prepared by this reaction is dependent upon the ph of the reaction medium. the phenacyl alpha-chymotrypsin produced at low ph is most probably the met-192 phenacylsulfonium salt, as proposed earlier, since it readily undergoes dealkylation using 2-mercaptoethanol. however, the phenacyl-enzyme prepared at ne ... | 1976 | 8093 |
| effect of temperature on tryptophan fluorescence of beta-lactoglobulin b. | the effect of heat on the conformation of bovine beta-lactoglobulin has been studied using intrinsic fluorescence spectroscopy. changes in the intensity, wave-length of maximum emission and emission peak width at half height of tryptophan fluorescence over the range 15-90 degrees c at ph 6.4-6.5 has allowed the environments of the two tryptophans in the molecule to be discriminated. at 20 degrees c both tryptophans are in hydrophobic environments. as the temperature is raised the conformation ch ... | 1976 | 8097 |
| human pancreatic-type ribonucleases with activity against double-stranded ribonucleic acids. | purified acid-thermostable ribonuclease (ribonucleate 3'-pyrimidino-oligonucleotidohydrolase, ec 3.1.4.22) from human pancreas degrades double-stranded rna at 2% the rate for single-stranded rna. the activities against single-stranded rna and double-stranded rna were shown to be due to a single enzyme with properties similar to bovine pancreatic rnaase a. for purposes of comparison the activities against double-stranded rna of crystalline ribonucleases of the whale, rat and cow were assayed and ... | 1976 | 8107 |
| public health importance of buffaloes and cows udder tissues. | | 1976 | 8937 |
| purification and some properties of a neutral protease from human leukocyte granules and its comparison with pancreatic elastase. | 1. a cationic protease has been purified from the granule fraction of blood-donor leukocytes by a preparative method including precipitation by acetone and chromatography on bio-gel a 1.5 m, cm-sephadex c-50 and sephadex g-g-75. 2. the ph optimum against denatured bovine hemoglobin is 7.4. gel chromatography indicated a molecular weight close to 23 000. 3. this neutral protease (ec 3.4.-.-) is able to split the synthetic esters z-ala-nph and acala3ome, its activity on the former substrate being ... | 1976 | 8109 |
| the reaction of the histidine residues of luteinizing hormone with ethoxyformyl anhydride. | bovine and porcine luteinizing hormones (b-lh, p-lh) and their subunits were treated by ethoxyformyl anhydride. the acylation of the histidine residues was followed by examination of the absorbance spectrum. all the histidine residues of the luteinizing hormone molecule can be modified at ph5. however 2 his in b-lh and 1 in p-lh appear to be much less reactive at ph 5 than the others and their acylated imidazols more labile at the same ph. at neutral ph, 2 histidines in b-lh (and 1 in p-lh) beco ... | 1976 | 8157 |
| the effect of temperature, solids content and ph on the survival of salmonellas in cattle slurry. | | 1976 | 8190 |
| blockade of histamine-induced contractions of guinea pig ielum by beta-haloalkylamines. | in the longitudinal muscle strip of guinea pig ileum phenoxybenzamine (pob) produces a maximum parallel shift of 0.7 log units in the dose-response curve to histamine. in the presence of sodium thiosulfate in the wash fluid the parallel shift whith retention of maximum response increases to about 2 log units, and a similar value is obtained for nethyl-n-(2-bromoethyl)-1-naphthylamine. the the agent n-ethyl-n- (2-chloroethyl)benzylamine produces a significantly smaller shift of dose-response curv ... | 1976 | 8204 |
| the action of a binary nonionic detergent on a kidney membrane fraction. | the disruption of a kidney cortex microsomal membrane preparation by a binary, nonionic detergent, was followed by using as markers, the changes in total protein content, and (na+, k+)-atpase in a supernatant fraction. both markers responded similarly to changes in ph, microsome concentration and detergent concentration, but responded differently for time-dependent studies. the (na+, k+)-atpase activity was increased 2.2-fold (76.1 mumoles pi/mg protein/h, 95% ouabain-sensitive) by a single dete ... | 1976 | 8217 |
| resistance of alkylated dna to degradation by deoxyribonuclease ii at neutral and acid ph. | methylation of a calf thymus dna substrate by dimethyl sulphate (dms) leads to an inhibition of deoxyribonuclease ii activity which is gradually lost with time. the extent of this initial inhibition is linearly related to the amount of methylated products in dna and quantitatively similar effects were found when the enzyme was used under either acid or neutral conditions. deoxyribonuclease ii was shown to produce 3'-phosphate termini under both acid and neutral conditions and thus, irrespective ... | 1976 | 8218 |
| alcohol dehydrogenase and retinol dehydrogenase in bovine retinal pigment epithelium. | | 1976 | 8324 |
| stability of the insoluble form of uridine kinase coupled to zn2+ or pb2+ ions. | partially purified calf brain uridine kinase precipitated by bivalent metal cations has been compared with the soluble enzyme fraction regarding its stability in the presence of inactivating factors. the freeze-dried preparations of uridine kinase precipitaated by pb2+ or zn2+ ions, althouth enzymatically highly active, are insoluble in aqueous solutions. the activity of metal-insolubilized enzymes disappears during their preincubation in acidic media or in the presence of silver ions. also tryp ... | 1976 | 8366 |
| hydrolysis-resynthesis equilibrium of the lysine-15--alanine-16 peptide bond in bovine trypsin inhibitor (kunitz). | catalytic amounts of bovine beta-trypsin, bovine alpha-chymotrypsin and porcine plasmin establish a true thermodynamic equilibrium between virgin (i) (reactive site lys15-ala16 peptide bond intact) and modified (i) (this bond hydrolyzed) bovine trypsin/kallikrein inhibitor (kunitz). the very slow reaction rates for attaining equilibrium are ph-dependent and differ for different enzymes. optimal rates are for beta-trypsin at ph 3.75, for alpha-chymotrypsin at ph 5.5, and for plasmin at ph 5.0. un ... | 1976 | 8370 |
| digestion of human immunoglobulin g by bovine cathepsin b1. | | 1976 | 8377 |