metal substitutions incarbonic anhydrase: a halide ion probe study. 19753
identification of adenylate cyclase-coupled beta-adrenergic receptors with radiolabeled beta-adrenergic antagonists. 197511
formation of transient complexes in the glutamate dehydrogenase catalyzed reaction.the reaction of glutamate dehydrogenase and glutamate (gl) with nad+ and nadp+ has been studied with stopped-flow techniques. the enzyme was in all experiments present in excess of the coenzyme. the results indicate that the ternary complex (e-nad(p)h-kg) is present as an intermediate in the formation of the stable complex (e-nad(p)h-gl). the identification of the complexes is based on their absorption spectra. the binding of the coenzyme to (e-gl) is the rate-limiting step in the formation of ( ...197539
specificity studies on alpha-mannosidases using oligosaccharides from mannosidosis urine as substrates.oligosaccharides containing terminal non-reducing alpha(1 leads to 2)-, alpha(1 leads to 3)-, and alpha(1 leads to 6)-linked mannose residues, isolated from human and bovine mannosidosis urines were used as substrates to test the specificities of acidic alpha-mannosidases isolated from human and bovine liver. the enzymes released all the alpha-linked mannose residues from each oligosaccharide and were most effective on the smallest substrate. enzyme a in each case was less active on the oligosac ...197570
the behavior of holo- and apo-forms of bovine superoxide dismutase at low ph.1. holo-superoxide dismutase from bovine erythrocytes has been shown to undergo a reversible structural modification in the ph 3-5 range. 2. the spectral alterations observed on changing from neutrality to ph 2 were: a slight attenuation of the 680 nm absorbance; the loss of the 450 nm shoulder, apparent in the optical spectrum of the native protein; and a new band appeared at 330 nm. the circular dichroism at 600 nm was essentially lost while a weak negative band appeared at approx. 380 nm and ...197582
membrane-bound enzymes. iii. protease activity in leucocytes in relation to erythrocyte membranes.protease activity was detected in membranes of human bovine erythrocytes prepared by the conventional procedures which include washing and removal of the "buffy layer". the enzyme was extracted by 0.75 m kcns or (nh4)2so4 and was activated by 0.4 to 0.5 m of the same salts. colored, particulate hide powder-azure, membrane fractions and soluble proteins such as hemoglobin, casein or albumin were susceptible to hydrolysis by the membraneous protease. partial purification of the enzyme was accompl ...197592
bovine mannosidosis--a model lysosomal storage disease. 1975100
analyses of rumen fluid from "sudden death", lactic acidotic and healthy cattle fed high concentrate ration. 1975351
the refined crystal structure of bovine beta-trypsin at 1.8 a resolution. ii. crystallographic refinement, calcium binding site, benzamidine binding site and active site at ph 7.0. 1975512
electrostatic side chain complementarity in collagen fibrils. 1975513
a hypothesis for the pathway of the thermally-induced unfolding of bovine pancreatic ribonuclease. 1975560
on the substrate specificity of cathepsins b1 and b2 including a new fluorogenic substrate for cathepsin b1. 1975577
relationship between bovine serum albumin structure and its chemical equilibria with hydrogen and 5-hydroxytryptamine ions.from the analysis of titration curves with hydrogen and 5-ht ions, it was found that the electrostatic interaction parameter of protein macroion and the number sites of 5-ht fixing were smaller over an acid and base ph range as compared to their values at neutral ph. our data were interpreted by the conformational changes which can be induced when bsa is exposed to denaturation by acid and alkali ph.1975699
determination of rhodanese activity using a ph-stat apparatus. 1975924
effect of ph and ionic strength on the catalytic and allosteric properties of native and chemically modified ox liver mitochondrial glutamate dehydrogenase. 1975966
evidence for histidine as another functional group of delta-aminolevulinic acid dehydratase from beef liver. 19751014
trypsin-catalyzed activation of aspartase. 19751021
beef liver l-glutamate dehydrogenase mechanism: presteady state study of the catalytic reduction of 2.oxoglutarate by nadph. 19751038
flavoxate and 3-methylflavone-8-carboxylic acid. assay methods in blood and urine, plasma-red cells repartition and stability.the following assay methods for pharmacokinetic studies on flavoxate (f) and on its main metabolite, i.e. 3-methylflavone-8-carboxylic acid (a), are described. 1. spectrophotometry for the assay of f and of a in plasma, 2. tlc-spectrodensitometry and glc for the assay of a in urine after acid hydrolysis, 3. tlc-spectrodensitometry for determining the f : a ratio in plasma or in urine. it was found that f hydrolyzes into a. this process depends on the ph and on the medium. in water, at ph 5.0, f ...19751048
acid and alkaline denaturation of superoxide dismutase.optical and esr spectra of erythrocyte superoxide dismutase denaturated with acid and alkali are described. sharp changes in activity and spectra were found. "residual" activity of alkaline denaturated protein was higher than of acidic denaturated sample. it is suggested that covalent bonding copper-nitrogen is essential for superoxide dismutase activity of the protein or synthetic copper complexes.19751099
letter: change in trypsin sensitivity during structural rearrangements in biological membranes. 19751101
the effect of oxidazable substrates and atp on the sensitivity of certain energy-dependent functions submitochondrial particles to phospholipases a, c and d.the effect of nadh, succinate and atp on the sensitivity of a number of energy-dependent functions of submitochondrial particles ot phospholipases a, c and d has been studied. it has been shown that in the conditions of oxidation of nadh and succinate by oxygen and also of atp hydrolysis, the decrease in the phosphorylating activity of the particles under the action of phospholipases c and d accelerates. no such acceleration has been observed with phospholipase a. for other two functions, i. e. ...19751116
raman studies of bovine serum albumin. 19761119
leucine aminopeptidase (bovine lens). effect of ph on the relative binding of zn2+ and mg2+ to and on activation of the enzyme.incubation of leucine aminopeptidase (bovine lens) (ec with various concentrations of mg2+ at various ph values in 1 m kcl and 0.155 m trimethylamine-hcl at 37 degrees confirms that mg2+ competes with zn2+ for binding only 1 site per 54,000-dalton subunit. the ratio of the apparent association constants (1kzn:1kmg = 1kzn/mg) at this site (site 1) was estimated to be 20,720 at ph 8.16, 10,570 at ph 8.44, 3,590 at ph 8.78, and 660 at ph 9.14. the decrease in values of 1kzn/mg with increas ...1976402
hydrophobic interaction determined by partition in aqueous two-phase systems. partition of proteins in systems containing fatty-acid esters of poly(ethylene glycol).in this report we describe a new method which is useful for measuring hydrophobic interactions between aliphatic hydrocarbon chains and proteins in aqueous environment. the method is based on partition of proteins in an aqueous two-phase system containing dextran and poly(ethylene glycol) and different fatty acid esters of poly(ethylene glycol). the partition is measured under conditions where contributions from electrostatic interactions are eliminated. the difference in partition of proteins i ...19751263
hepatic nucleases. extrahepatic origin and association of neutral liver ribonuclease with 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 ...19751273
biochemical aspects of the visual process. xxxi. chemical modification studies on rod outer segment retinol dehydrogenase. 19751283
isolation and characterization of pepsin-treated type iii collagen from calf skin.calf skin collagen was solubilized by incubating acid-extracted calf skin with pepsin at ph 2.0 and 25 degrees c, conditions that did not cause degradation of the triple helical region of collagen. type iii collagen was separated from type i collagen by differential salt precipitation at ph 7.5. the isolated type iii collagen contained mainly gamma and higher molecular weight components cross-linked by reducible and/or non-reducible bonds. the isolated alpha1 (iii) chains had an amino acid compo ...19751337
a complex of cardiac cytochrome c1 and cytochrome c.the interactions of cytochrome c1 and cytochrome c from bovine cardiac mitochondria were investigated. cytochrome c1 and cytochrome c formed a 1:1 molecular complex in aqueous solutions of low ionic strength. the complex was stable to sephadex g-75 chromatography. the formation and stability of the complex were independent of the oxidation state of the cytochrome components as far as those reactions studied were concerned. the complex was dissociated in solutions of ionic strength higher than 0. ...1976401
proteolytic enzymes of the k-1 strain of streptomyces griseus obtained from a commercial preparation (pronase). purification and characterization of the carboxypeptidase.we described earlier the facilitated purifications of the trypsin and aminopeptidase components present in pronase (vosbeck, k. d., chow, k. -f., and awad, w. m., jr. (1973) j. biol. chem. 248, 6029-6034). a partially resolved protein mixture left over after one of the steps in that procedure was passed through a sephadex g-75 column. by this means, a component with carboxypeptidase activity was separated from associated serine endopeptidases. further purification of this exopeptidase to apparen ...1976399
protein inhibitor of acid deoxyribonucleases. improved purification procedure and properties.a method is described for the extensive purification of acid deoxyribonuclease (acid dnase) and its specific inhibitor from beef liver, the existence of which had been only supported by indirect evidence. by the use of insolubilized acid deoxyribonuclease, eight other proteins interacting with the enzyme have been detected. one of them (molecular weight, 59,000) was identified as responsible for phosphodiesterase activity which is often a contaminant of dnase preparations. acid dnase (free of ph ...1976396
oxidation of nadph by submitochondrial particles from beef heart in complete absence of transhydrogenase activity from nadph to nad.treatment of submitochondrial particles (etp) with trypsin at 0 degrees destroyed nadph leads to nad (or 3-acetylpyridine adenine dinucleotide, acpyad) transhydrogenase activity. nadh oxidase activity was unaffected; nadph oxidase and nadh leads to acpyad transhydrogenase activities were diminished by less than 10%. when etp was incubated with trypsin at 30 degrees, nadph leads to nad transhydrogenase activity was rapidly lost, nadph oxidase activity was slowly destroyed, but nadh oxidase activi ...1975395
serum stimulation of phosphate uptake into 3t3 cells.the stimulation by calf serum of phosphate uptake into 3t3 cells results from a change in maximum velocity of the transport process with no change in the michaelis constant. only arsenate among a series of inorganic structural analogs of phosphate inhibited phosphate uptake indicating a high specificity for the process. the arsenate inhibition was competitive in nature. papaverine, theophylline, and protaglandin e1, drugs known to maintain high intracellular levels of camp, had little effect on ...19761399
on the mechanism of ketogenesis and its control. purification, kinetic mechanism and regulation of different forms of mitochondrial acetoacetyl-coa thiolases from ox liver.1. two mitochondrial forms of acetoacetyl-coa thiolases designated as enzyme a and enzyme b were crystallized from ox liver. they could be shown to be homogenous by polyacrylamide gel electrophoresis. 2. in direction of acetoacetyl-coa cleavage enzyme a shows a double competitive substrate inhibition when acetoacetyl-coa is varied at different fixed coa concentrations. with enzyme b a parallel kinetic pattern is obtained when acetoacetyl-coa is varied at different fixed coa concentrations. in di ...19751256
distribution and removal of added mercury in milk.distribution patterns of added mercury in raw whole milk after equilibration for 30 min and 2 h at 37 c showed a distribution among acid casein, whey proteins, fat globule membrane, and soluble fat globule membrane of 33, 28, 16, and 2%. on the basis of protein content, the fat globule membrane had the highest amount of mercury. mercury added to milk as mercuric chloride was removed by treatment with thiolated aminoethyl celluloses and reduced human hair. in a 5 min treatment, 70, 43, and 41% of ...19751421
porcine chymotrypsin a-pi, a more acidic chymotrypsin.a kinetic study of procine chymotrypsin a-pi revealed two characteristic properties of this type of chymotrypsin: 1. porcine chymotrypsin a-pi, like bovine chymotrypsin b-pi does not bind proflavin, which is a competitive inhibitor of bovine trypsin and chymotrypsin a-alpha. 2. the ph profiles of the steady-state parameters show the two usual important pk's. the basic one, pk2 = 9.6, affects both km and kcat/km and probably controls the binding conformation of chymotrypsin. the acidic one, pk1 = ...19751143
some properties of proteolysis by polymorphonuclear leukocyte-granule extracts.the extracts of granules of human polymorphonuclear leukocytes hydrolyzed a variety of proteins including human and bovine hemoglobin, human fibrinogen, human and bovine serum albumin, bovine elastin, and casein. the hydrolysis of all the proteins except fibrinogen and elastin was increased by addition of urea. various inhibitors of trypsin, kallikrein, plasmin, clr, cls, and other proteolytic enzymes had no inhibitory effect. slight inhibition was observed with polyanethol sulfonate and strong ...19761449
effect of surfactant monomers on chloramphenicol association to an albumin-lecithin complex: a model for modified drug absorption.the binding of chloramphenicol to an albumin-lecithin complex in the presence or absence of premicellar concentrations of both ionic and non-ionic surfactants has been examined. long chain, strong ionic detergents, such as sodium dodecyl sulphate or cetyltrimethylammonium bromide, severely perturb protein structure and eventually allow full separation of the complex into lecithin and albumin-detergent complexes. the dissociation process is reversible upon the removal of the detergent by exhausti ...19751488
detection and partial characterization of lipoprotein lipase in bovine aorta.extracts of acetone-ether powders of bovine thoracic aorta contain lipase activity which has an alkaline ph maximum (7.8-8.4) and is stimulated 4-10-fold by adding serum or isolated apolipoprotein-glutamate to the assay mixture. serum activation is completely reversed by isolated apolipoprotein-serine or apolipoprotein-alanine. lipolysis is strongly inhibited by nacl (0.5 m) and protamine sulfate (1 mg/ml) and partially inhibited by heparin. based on these characteristics, the lipase is identifi ...19751087
conformational properties of bovine plasma albumin with a cleaved internal peptide shown previously, proteinases frequently associated with plasma albumin samples catalyze a very limited and specific cleavage of the albumin molecule when it exists in the f conformational state near ph 3.7. the primary proteolytic product, bpa, has a molecular weight similar to or identical with that of the parent protein but yields two large fragments of molecular weight approximately 46000 and 23000 on reduction. evidence is presented here that cleavage occurs within the disulfide loop bet ...19751086
proteins in the luminal fluid from the bovine oviduct.oviducal fluid was collected by cannulation from four cows and by irrigation from fifteen slaughtered cows. the proteins in the fluid were examined by polyacrylamide gel electrophoresis at ph 4-5 and ph 8-9, isoelectric focusing on polyacrylamide, immunodiffusion, immunoelectrophoresis, affinity chromatography and gel filtration. the macromolecular components found were mainly serum proteins but small amounts of other proteins were detected in oestrous and dioestrous samples by electrophoresis a ...19751525
transfer of gases and metabolites in the equine placenta: a comparison with other species.mares and fetuses with indwelling catheters in the umbilical and uterine vessels have been used to monitor transplacental blood gas tensions, ph, o2 affinities and the concentration of various metabolites in fetal and maternal blood during late gestation. measurements of umbilical and uterine blood flows and arterio-venous differences enabled the uptake of o2 and glucose by the fetus and the uterus to be estimated. the present findings are compared with those from other species in comparable con ...19751529
the effect of pentoxifyllin on the cyclic amp-system in thrombocytes. 19751626
ion transport and respiratory control in vesicles formed from reduced nicotinamide adenine dinucleotide coenzyme q reductase and phospholipids.nadh-coenzyme q reductase from bovine heart mitochondria (complex i) was incorporated into phospholipid vesicles by the cholate dialysis procedure. mixtures of purified phosphatidylcholine and phosphatidylethanolamine were required. oxidation of nadh by coenzyme q1 catalyzed by the reconstituted vesicles was coupled to proton translocation, directed inward, with an h+/2e ratio greater than 1.4. similar experiments measuring proton translocation in submitochondrial particles gave an h+/2e ratio o ...1975386
reconstitution of ion transport and respiratory control in vesicles formed from reduced coenzyme q-cytochrome c reductase and phospholipids.reduced coenzyme q-cytochrome c reductase from bovine heart mitochondria (complex iii) was incorporated into phospholipid vesicles by the cholate dialysis procedure. soybean phospholipids or mixtures of purified phosphatidylcholine, phosphatidylethanolamine, and cardiolipin could be used. oxidation of reduced coenzyme q2 by the reconstituted vesicles with cytochrome c as oxidant showed the following energy-coupling phenomena. 1. protons were translocated outward with a coupling ratio, h+/2e, of ...1975385
the active form of cytochrome p-450 from bovine adrenocortical mitochondria.cytochrome p-450 from bovine adrenocortical mitochondria exists in three forms of molecular weight: 850,000 (protein 16), of one-half (protein 8), and of one-quarter of this value (protein 4). the forms of the enzyme are named according to the number of subunits and all appear to be active in converting cholesterol to 3beta-hydroxy-5-pregnen-20-one (side chain cleavage) (shikita, m., and hall, p.f. (1973) j. biol. chem. 248, 5606). to determine whether all three forms are active at their charact ...1975383
human placental delta5-3beta hydroxysteroid dehydrogenase activity (delta5-3beta hsdh): intracellular distribution, kinetic properties, retroinhibition and influence of membrane delipidation.delta5-3beta hsdh activity has been assayed either by spectrophotometric method or by use of radioactive substrates. the enzymatic activity is equally distributed between mitochondrial and microsomal fractions verified by electronic microscopy. the specific activity is comparable in both fractions, as well as the optimal ph and the km for nad and for the substrates. the delta5-3beta hut optimal ph, specific activity and sensitivity to the inhibitory action of various steroids are different when ...19751879
hydrolysis of insoluble collagen of bull bones by streptomyces griseus crystalline protease.hydrolysis of collagen was studied in the bull bone tissues by the str. griseus crystalline protease. the amount of collagen hydrolyzed by it composed 6.6% and 16% after 4-hour and 6-hour hydrolysis, respectively. when the enzyme:substrate ratio is 1:50 hydrolysis proceeds most intensively; with a decrease in the ratio up to 1:1000 the average amount of peptides increase from 2.6 up to 4 amino acidic residua, respectively. under conditions of denaturated collagen hydrolysis the content of hydrox ...19751884
prevention of sterility in cows. 19751893
in vitro effect of leukocytic and thymic histones and their fractions on the activity of the causative agent of was found in studying the antimeningococcus activity of the leukocytic and thymus histones and their fractions that both histones were capable of neutralizing in vitro the activity of the causative agent of meningopneumonia (mp). the neutralization effect was chiefly associated with the f3 fraction rich in arginine and depended on the duration of the histone fraction contact with the mp causative agent, the weight concentration of the histone and the ph of the incubation medium.19751947
mannosidosis of angus cattle: a prototype control program for some genetic diseases. 19751978
combined use of bucolome and pyrazolone derivatives (ii). complex formation due to interaction between bucolome and pyrazolones.we have already reported that bucolome (bcp), a non-steroidal anti-inflammatory agent, potentiates significantly the analgesic and antipyretic effects of pyrazolones which are substituted by alkylamino group at 4-position of the pyrazolone ring. physical and quantum chemistry were applied to the mechanism of this synergistic action. the solubility of bcp was markedly increased in proportion to elevation of aminopyrine (am) concentration, but not by a combination with isopropylantipyrine (ip). th ...1975282
immunization against q-fever of naturally infected dairy cows.dairy cows infected naturally with coxiella burnetii as evidenced either by presence of phase ii agglutinating antibodies in the blood or by shedding c. burnetii in the milk, were vaccinated subcutaneously with formalin-killed phase i c. burnetii organisms. attempts to demonstrate c. burnetii in the milk of vaccinated dairy cows 47 days after vaccination were negative, while continuous shedding of c. burnetii in the milk of control non-vaccinated dairy cows was repeatedly demonstrated in the cou ...19751994
effects of external and internal arthropod parasites on domestic livestock production. 19762093
effects of stereochemical structures of tetrahydropterins on tyrosine hydroxylase. 19752173
liver microsomal beta-glucuronidase and udp-glucuronyltransferase.both udp-glucuronyltransferase (gt) and beta-glucuronidase (betag) were assayed in untreated liver microsomes. optimum assay conditions were established with rat liver microsomes using p-nitrophenol (pnp) and its glucuronide (pnpga) at the ph optima of gt (7.5) and betag (4.5). the activities of the two enzymes were compared using microsomes from rats, mice, pigs, cattle and horses, with pnp, pnpga, and phenolphthalein as substrate, in the presence of various cofactors and inhibitors at ph 7.5 a ...1975230
conformation of gonadotropin releasing hormone.the conformation of the gonadotropin releasing hormone (gn-rh), whose primary sequence is pglu-his-trp-ser-tyr-gly-leu-arg-pro-glynh2, and of several of its structural analogues has been studied by circular dichroism, optical rotatory dispersion, and fluorescence spectroscopy. the effects of ph, guanidine, and temperature on fluorescence emission have also been examined. titration data demonstrate that the histidine and tyrosine residues are free of any mutual interactions. the similarity of emi ...19762282
isolation, chemical, and physical properties of alpha-1-antitrypsin.a method of isolation of alpha-1-antitrypsin (alpha-1-at) in good yield from normal human plasma is described. a key step was affinity chromatography employing an antiserum which had been depleted of alpha-1-at antibodies. the final preparations were homogeneous by immunological and physicochemical criteria. the specific activity of the purified alpha-1-at was 0.363 mg of active bovine trypsin inhibited per 1.0 mg of inhibitor. polyacrylamide gel patterns at both alkaline and acid ph of highly p ...19762286
ecological observation of the 137cs-contamination in beef of animals from the southern-bavarian area.certain climatic and edaphic conformations in the bavarian sub-alpine mountains and in the alps favor above all the development of a land utilization system and farm structures similar to those in the northern part of scandinavia. in 1963/64, the years of the highest environmental contamination up to the present, we established in 600 beef samples from the round or shoulder of male and female cattle (mainly highland cattle) close connections between the 137cs-contamination of green crop and the ...1975229
multiple forms of casein kinase from rabbit erythrocytes.two rabbit erythrocyte casein kinases, gtp:casein kinase i and gtp:casein kinase ii, have been purified 29 000- and 47 000-fold, respectively. studies employing sucrose density gradient centrifugation indicate that kinase i has a molecular weight of about 9.5 - 10(5) (25 s) and kinase ii about 1.4 - 10(6) (32 s). these enzymes can utilize either atp or gtp as the phosphoryl donor. among various protein substrates examined, these kinases catalyze the phosphorylation of casein greater than 50% dep ...197576
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 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 ...197574
glial fibrillary acidic protein from bovine and rat brain. degradation in tissues and homogenates.compared with human material glial fibrillary acidic protein isolated from bovine, rat and mouse brain was remarkably homogeneous and migrated as a single band at 54 000 mol. wt. on sodium dodecyl sulfate gel electrophoresis. the protein was extremely susceptible to proteolysis and lower molecular weight components were invariably isolated together with the major species when the brain was not rapidly frozen. further degradation of the 54 000 mol wt. polypeptide in bovine tissues incubated at 24 ...19762294
the interaction of bovine erythrocyte superoxide dismutase with hydrogen peroxide: inactivation of the enzyme.bovine erythrocyte superoxide dismutase was slowly and irreversibly inactivated by hydrogen peroxide. the rate of this inactivation was directly dependent upon the concentrations of both h2o2 and of enzyme, and its second-order rate constant at ph 10.0 and 25 degrees was 6.7 m-1 sec-1. inactivation was preceded by a bleaching due to rapid reduction of cu2+ on the enzyme, and following this there was a gradual reappearance of a new absorption in the visible region, which was coincident with the l ...197549
purification and specificity of prolyl dipeptidase from bovine kidney.prolyl dipeptidase (iminodipeptidase, l-prolyl-amino acid hydrolase, ec was purified 180-fold from bovine kidney. the enzyme which was obtained in a 10% yield was completely separated from a number of known kidney peptidases including an enzyme of very similar substrate specificity, proline aminopeptidase (l-prolyl-peptide hydrolase, ec the specific activity of the enzyme with l-prolylglycine as substrate is 1600 units of activity per mg protein. optimum activity of the enzy ...19762303
bovine liver dihydrofolate reductase: purification and properties of the enzyme.a purification procedure is reported for obtaining bovine liver dihydrofolate reductase in high yield and amounts of 100-200 mg. a key step in the procedure is the use of an affinity gel prepared by coupling pteroyl-l-lysine to sepharose. the purified reductase has a specific activity of about 100 units/mg and is homogeneous as judged by analytical ultracentrifugation, polyacrylamide gel electrophoresis, and titration with methotrexate. the products of the first step of edman degradation indicat ...197545
survival of salmonellae during pepperoni manufacture.survival of salmonellae in artificially contaminated beef-pork mixtures (approximately 10(4) salmonellae/g) was studied in pepperoni prepared by either a natural flora or lactic starter culture fermentation or in nonfermented sausages. the pepperoni did not become salmonellae free during the usual commercial 15 to 30-day drying period. salmonella dublin was present in all products, fermented or unfermented, after 42 to 43 days of drying. at a lower level of contamination, 10(3)/g, s. dublin coul ...1975951
experimental ulcer. 1975855
amylase of the thermophilic actinomycete thermomonospora vulgaris.alpha-amylase of the thermophilic actinomycete thermomonospora vulgaris was partially purified. maximal enzyme activity was obtained at 60degreec and ph 6.0. km value was l.4%. the effect of some metal salts on enzyme activity was studied. enzyme activity was inhibited by by kcn, edta, and iodoacetate. inhibition by edta was completely nullified by cacl2, but the inhibition by iodoacetate was not overcome by 2-mercaptoethanol. exposure of the enzyme to ph 7.0 and 9.0 for 2 hr. did not affect the ...1975848
salt effects on the denaturation of dna. v. preferential interactions of native and denatured calf thymus dna in na2so4 solutions of varying ionic strength. 19762350
prostaglandins in pyometrial fluid from the cow, bitch and ferret.1 pyometra is a disorder of the uterus usually associated with bacterial infection plus obstruction. 2 large quantities of fluid often collect in the uterus during this condition. 3 pyometrial fluid obtained from three species was found to contain prostaglandin f2alpha, usually in large quantities. 4 prostaglandin e2 was present in smaller quantities in five of the six samples. 5 these findings are discussed in relation to the known occurrence of prostaglandins in inflammatory fluid, and to the ...19752358
methodological simplifications in radioimmunoassay of urinary aldosterone.simplification of radioimmunoassay procedures of urinary aldosterone-18-glucuronide was attempted, taking into consideration the aspects implied by the hydrolysis of urine and the assay itself. the procedure standardized for the hydrolysis step (samples diluted with a two-fold volume of 0.2 n hcl and incubated at 30 degrees c for 16-24 h) proved suitable in terms of practicability and accuracy. aldosterone antisera, raised in the rabbit against an aldosterone-3-bovine albumin conjugate, were sel ...19762397
lymphocyte subpopulations. human red blood cell rosettes.human red blood cells (hrbc) even without prior neuraminidase treatment, could form rosettes with human peripheral blood lymphocytes in vitro. the optimum conditions for forming these rosettes were a ph of 7-0 and a medium with 5% bovine serum albumin (bsa). rosette proportions became much less at a different ph or using lower concentrations of bsa, or replacing bsa with foetal calf sera (fcs) or human sera. rosette formation was also promoted by prior treatment of hrbc or lymphocytes with neura ...19752404
determination of the proteolytic activity of beef liver by means of natural substrates labed with 125 i.there is a description of the determination of the enzymatic activity of acid proteinases: the method is based on the use of 125j-labelled natural protein substrates. labelled albumin 125j, globulin 125j, and insulin 125j were tested for the determination of activities. all the substrates were hydrolyzed with the enzymes of the supernatant fraction (106 000 g) of beff liver homogenate in the zone of acid ph. optimum comditions of enzymatic reaction were tested, the dependence of reaction on the ...1975841
some properties of "soluble" na+ and k+-atpase obtained from various subcellular membrane structures of the brain by use of non-ionic detergents.a comparative study was carried out of some properties of "soluble" na+, k+-atpase obtained from different subcellular membrane brain structures by means of non-ionic detergents of triton x-100 and digitonin. it is established that temperature and ph-optima of "soluble" na+, k+-atpase are close to these optima of the initial membrane preparations. a certain difference is observed in the dynamics of temperature and ph-dependence of na+, k+-atpase activity in the extracts from different subcellula ...1975831
4 m guanidine hydrochloride applied to the isolation of dna from different sources. 19762505
the effect of ph on human serum dopamine beta-monooxygenase. 19752531
the role of mg and ca ions in muscle contraction (author's transl). 1975739
non-specific alkaline phosphomonoesterases of eight species of digenetic trematodes.alkaline phosphatases from different trematodes occupying the same habitat have identical ph otima but different levels of enzyme activities. isoparorchis hypselobagri, from the fish wallago attu, shows four to six times more enzyme activity than fasciolopsis buski, gastrodiscoides hominis and echinostoma malayanum, from the pig sus scrofa, and fasciola gigantica, gigantocotyle explanatum, cotylophoron cotylophorum and gastrothylax crumenifer, from the buffalo bubalus bubalis. at least two peaks ...19751442
mitochondrial malate dehydrogenase of bovine cerebrum. characterization and mechanisms of inhibition by silver ions.attempts were made to characterize mitochondrial malate dehydrogenase l-malate: nad+ oxidoreductase, ec (m-mdh) purified from bovine cerebrum and to elucidate the mechanisms responsible for inhibition of the enzymic activity by ag+. the molecular weights of the native enzyme and its subunits were 54,000-55,000 and 30,000-32,000, respectively. in general, the physiochemical and catalytic properties of bovine cerebral m-mdh was not very different from those of other corresponding mammalia ...19752592
inhibition by superoxide dismutase of methemoglobin formation from oxyhemoglobin.the formation of methemoglobin from oxyhemoglobin in a solution containing photoreduced riboflavin and oxygen was inhibited by superoxide dismutase. the rate of the reaction was ph-dependent in the range of 6.8 to 7.8, increasing as the ph was reduced. inhibition by superoxide dismutase was enhanced as the edta concentration increased and was dependent on enzymatic activity. under conditions in which superoxide dismutase inhibition was incomplete, catalase inhibited the reaction but mannitol had ...19762597
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 ...19762600
identification of albumin as the serum factor essential for the growth of activated human lymphocytes.albumin from human, bovine, or rabbit serum supported the growth of concanavalin a-stimulated human thymus-derived lymphocytes equally well. this activity was completely abolished by pepsin digestion. it was shown for bovine serum albumin that the albumin molecule itself, and neither an impurity nor a factor bound to albumin was essential for the growth of lymphocytes. this conclusion was based on observations that the growth-promoting activity could not be removed from albumin, and that the spe ...19762610
cathepsin, phosphoprotein-phosphatase and acid phosphatase in the soluble fraction of the cattle brain cortex: purification and properties (author's transl).cattle brain cortex was homogenised in 0, 29 mol/1 sucrose and centrifuged at 101 000 x g. the supernatant contains the majority of 3 enzymes participating in protein turnover: cathepsin (ec, phosphoprotein phosphatase (ec and acid phosphatase (ec they were separated by chromatography on sephadex g 200 in neutral buffer. the cathepsin was purified up to 380 fold by gel filtration on sephadex and column electrophoresis. the ph optimum of cathepsin was 5.7. at 37 degr ...19762648
isolation from bovine brain of a fraction containing capillaries and a fraction containing membrane fragments of the choroid plexus.combined differential and density gradient centrifugation was used for the isolation of a capillary-rich fraction from the cerebral cortex and a brush border containing fraction from the bovine choroid plexus. the activities of gamma-glutamyl transpeptidase and several other marker enzymes were monitored during the fractionation procedure. electron microscopic examination showed a membrane-rich fraction in the choroid plexus high in the gamma-glutamyl transpeptidase and 5'-nucleotidase activitie ...19762650
synthesis and enzymic activity of some novel xanthine oxidase inhibitors. 3-substituted 5,7-dihydroxypyrazolo(1,5-alpha)pyrimidines.a series of 3-substituted 5,7-dihydroxypyrazolo1,5-alphapyrimidines containing various aromatic phenyl- (3e), 3-pyridyl- (3f), p-bromophenyl- (3g), p-chlorophenyl- (3h), p-acetamidophenyl- (3i), p-tolyl- (3j), m-tolyl- (3k), 3,4-methylenedioxyphenyl- (3m), or naphthyl- (3n) or nonaromatic hydrogen- (3a), nitro- (3b), bromo- (3c), or chloro- (3d) substituents in the 3 position was synthesized and tested as inhibitors of xanthine oxidase. the compounds (3a-m) were synthesized by condensation of th ...19762778
purification of tyrosine hydroxylase from pheochromocytoma tumors. 19762828
the temperature dependence of 8-3hadenosine labelling of the perfused bovine and canine adrenal gland. 19751498
effects of psychotropic drugs on prostaglandin biosynthesis in vitro. 19751505
enzyme induction (third of three parts). 19761671
immunological similarity between nadh-cytochrome b5 reductase of erythrocytes and liver a number of animal species soluble nadh-cytochrome b5 reductase of erythrocytes was compared with membrane-bound nadh-cytochrome b5 reductase of liver microsomes by using an antibody to purified nadh-cytochrome b5 reductase from rat liver microsomes. the results obtained indicated clearly that they are immunologically very similar to each other. the data with erythrocyte ghosts suggested that cytochrome b5 and nadh-cytochrome b5 reductase are also present in the ghost.19762319
distribution of prostaglandin e 9-ketoreductase and nad+-dependent and nadp+-dependent 15-hydroxyprostaglandin dehydrogenase in the renal cortex and medulla of various species.regional distributions of pge 9-ketoreductase and 15-hydroxy-prostaglandin dehydrogenase were examined in the cytoplasmic fractions from the kidneys of seven species. all species contained an nadph-dependent reductase, as well as nad+- and nadp+-dependent dehydrogenases in both cortex and medulla. a previously unrecognized cytoplasmic nadh-dependent pge 9-ketoreductase was also detected in the cortex and medulla of rat and bovine kidney. total nad+- and nadp+-dependent dehydrogenase activity was ...19752961
microcolorimetric study of the association of trypsin with a pancreatic inhibitor.enthalpy of the association of trypsin with pancreatic inhibitor from bovine pancreas at 25 degrees c as a function of ph and ionic strength is estimated. the dependence of the enthalpy on ph is of an extremal character with a minimum at ph 7.6 (delta h degrees =-10.3 ccal/mole). the increase of ionic strength with the addition of licl, kcl and cscl at ph 7.6 leads to be increase of delta h degrees. possible mechanisms of enthlpy changes depending on medium conditions are considered.19752326
studies on fragments of rod outer segments from bovine retinas.monolayers of fragments of our rod segments were formed at an air-water interface. the area of these particles was measured as a function of the ph of the aqueous phase. a maximum area was measured at ph 6.5. the film was characterised by measuring the decrease in surface pressure, after compression, and the half time required to reach constant pressure. at a ph between 6 and 7 the decrease in surface pressure was a minimum. irradiation of films of fragments resulted in a decrease in surface pot ...19753051
quantitative removal of carrier ampholytes from protein fractions derived from isoelectric focusing. 19753125
a study of the lysyl residues in the basic pancreatic trypsin inhibitor using 1h nuclear magnetic resonance at 360 mhz.fourier transform 1h nuclear magnetic resonance (nmr) experiments at 360 mhz using convolution difference techniques to improve the spectral resolution were employed to investigate the resonances of the lysyl residues in bovine pancreatic trypsin inhibitor. the observations in both native protein and in chemically modified protein containing nepsilon-dimethyllsysine show that three of the four lysines extend predominantly freely into the solvent, whereas lysine-41 is involved in an intramolecula ...19762474
a reporter group delivery system with both absolute and selective specificity for thiol groups and an improved fluorescent probe containing the 7-nitrobenzo-2-oxa-1,3-diazole moiety.1. 4-(n-2-aminoethyl2'-pyridyl disulphide)-7-nitrobenzo-2-oxa-1,3-diazole (compound i) was synthesized and evaluated as a fluorescent labelling reagent for thiol groups. 2. the design of compound (i) as one example of a general type of reporter group delivery reagent (2-pyridyl-s-s-x, where x contains an environmentally sensitive spectroscopic probe) is discussed. 3. the electronic absorption spectrum of compound (i) was determined over a wide range of ph and the spectral changes that accompany ...19753168
anion and amine uptake and uncoupling in submitochondrial particles.1. unlike chloroplasts, submitochondrial particles are not uncoupled by nigericin + kcl or nh4cl. also the uncoupling effect of lipophilic anions is largely independent of the addition of weak bases. 2. low concentrations of permeant anions cause a shift of the steady-state energy level rather than a cycle of energy utilization. the degree of inhibition of atp synthesis by tetraphenylboron is larger than required for the uptake of the anion. 3. lipophilic anions such as bromthymolblue, bromcreso ...19762477
translational control of protein synthesis in stimulated wi-38 fibroblasts.a cell-free protein synthesis system employing ribosomes from wi-38 human diploid fibroblasts was developed and its optimum mgc12 and kc1 levels and ph value found. the rate at which ribosomes are able to incorporate radioactive leucine into proteins (14cleucine incorporation/10 min/100 mug rrna) and the number of growing peptide chains 3hpuromycinpeptides formed/100 mug rrna) was determined. when confluent monolayers of wi-38 cells were stimulated to proliferate by serum, a transient increase i ...19763222
comparison of four proteoglycans in terms of their interactions with poly(l-arginine). 19763231
circular dichroism of collagen, gelatin, and poly(proline) ii in the vacuum ultraviolet. 19763232
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