| on the specificity of bovine spleen cathepsin b2. | the specificity of bovine spleen cathepsin b2 has been investigated by means of some natural oligo- and polypeptides, i.e. glucagon, melittin, insulin a and b chain, bradykinin, angiotensin i and ii, oxytocin acth, clupein and salmin. the enzyme is primarily a carboxypeptidase which hydrolyzes peptide linkages of most amino acids common to proteins. in addition, cathepsin b2 displays amidase and esterase activity without requiring a free carboxyl group. the main ph optimum is between 4 and 5, in ... | 1976 | 12811 |
| mannosyltransferase activity in calf pancreas microsomes. formation of 14c-labeled lipid-linked oligosaccharides from gdp-d-14cmannose and pancreatic dolichyl beta-d-14cmannopyranosyl phosphate. | calf pancreas microsomes incorporated radioactive d-mannose from gdp-d-14cmannose into lipid-bound oligosaccharides extracted with chloroform/methanol/water (10/10/2.5, v/v). several products, which probably differed in the size of the oligosaccharide moiety, were labeled. these could be partially resolved by thin layer chromatography and deae-cellulose chromatography. the labeled lipid-bound oligosaccharides were retained on deae-cellulose more strongly than synthetic dolichyl alpha-d-14cmannop ... | 1977 | 13065 |
| transmembrane electrochemical h+-potential as a convertible energy source for the living cell. | | 1977 | 14031 |
| rhodopsin in model membranes: charge displacements in interfacial layers. | a model membrane was developed in which interfacial layers of rhodopsin were reoriented onto one side of a thin teflon film separating two aqueous compartments. flashes evoked fast photoelectric signals (1 ms) that originated from capacitative charge displacements of oriented rhodopsin upon bleaching. the photoelectric responses of rhodopsin in the model membrane are compared with the early receptor potential of photoreceptor cells; it is concluded that the signals in both systems originate from ... | 1977 | 13363 |
| a ph-dependent interaction between histones h2a and h2b involving secondary and tertiary folding. | it has been shown by high-resolution proton magnetic resonance (pmr) spectroscopy and circular dichroism (cd) that an h2a/h2b histone complex exists after salt extraction of these histones from chromatin and that this complex can be fully renatured from both urea-denatured acid-extracted and from urea-denatured salt-extracted histones. the histone complex is shown to involve specific secondary and tertiary structure. formation of this complex is observed to be critically dependent on ph, occurri ... | 1976 | 12962 |
| protease activity in female ornithodoros tholozani ticks. | the protease activity in guts of ornithodoros tholozani females was studied in vitro. the intracellular protease in ornithodoros tholozani guts has a ph optimum of about 3.0. hemoglobin is the preferred substrate, and bovine serum albumin is digested very slowly. in this respect the protease resembles cathepsin d. unfed ticks contain a small amount of protease in the gut. after feeding the level of protease increases gradually for several days until peak protease activity is attained. the level ... | 1976 | 13632 |
| purification and properties of acetyl coenzyme a synthetase from bakers' yeast. | acetyl-coa synthetase, utilized in a coupled reaction system, has been shown to be applicable to the spectrophotometric determination of propionic and methylmalonic acids in biological fluids. the isolation of acetyl-coa synthetase from yeast is simpler than the purification from mammalian sources. this study also presents some properties of the yeast enzyme and compares it to the more extensively studied enzyme isolated from ammmalian tissue. isolation and purification yielded a preparation wit ... | 1977 | 13070 |
| the role of cyclic amp in the activation of tyrosine hydroxylase during nerve stimulation proceedings. | | 1977 | 13451 |
| sustrate-specificity of glucomylase (e.c. 3.2.1.3) exemplified by p-nitroaniline n-glucosides. | the present paper supplements the previous investigations on the mechanism of reactions catalyzed by amylolytic enzymes. the performed experiments corroborated the data on transglucosylative properties of animal glucoamylases which were found to depend on the structure and concentration of substrate. the p-nitroanilines were first introduced in this type of research enabling to find the differences of activity mechanism of animal glucoamylases and aspergillus niger glucoamylase. in complement to ... | 1976 | 13765 |
| sulphatases, lysosomes and disease. | | 1976 | 13772 |
| xanthine oxidase: a source of hydrogen peroxide in bovine thyroid glands. | | 1977 | 14288 |
| effects of induced cryptorchidism in bulls. | ninety bull calves were made cryptorchid by forcing the testes into the abdominal cavity and ablating the scrotum with elastrator rings. normal spermatogenesis was seen following histological examination of some of the testes approximately 17 months after the operation. no effect on bull behaviour was noted in the cryptorchids although plasma testosterone levels were lower than those reported for bulls. it is possible that this method may leave some of the cryptorchids fertile. | 1976 | 13775 |
| myocardial function during acute hypoxia in the calf. | hemodynamics and myocardial contractility were evaluated in five unanesthetized calves during acute hypocapnic and isocapnic hypoxia and during acute hypocapnic hypoxia with beta-adrenergic blockade. both hypocapnic and isocapnic hypoxia, with mean pao2 levels of 33.1 and 39.1 mm hg respectively, produced a decline in stroke volume and index, while cardiac output and index were maintained at normoxic control levels by an increase in heart rate. evaluation of myocardial contractility indices sugg ... | 1976 | 13780 |
| energy-dependent contraction of swollen mitochondria: activation by nigericin. | | 1977 | 13791 |
| interaction of acetazolamide and 4-nitrothiophenolate ion with bivalent metal ion derivatives of bovine carbonic anhydrase. | the stability and rate constants for the interaction of acetazolamide (diamox) and 4-nitrothiophenolate ion (ntp) with the bivalent mn, co, ni, cu and cd forms of bovine carbonic anhydrase have been measured by utilizing the distinct visible spectra of each metalloenzyme-ntp adduct. differing stabilities of the various ntp and (particularly) diamox complexes reside mainly in varying values for the dissociation rate constants (kd). intrinsic formation rate constants (for the acid form of the enzy ... | 1977 | 13818 |
| determination of ionization state by resonance raman spectroscopy sulfonamide binding to carbonic anhydrase. | resonance raman (rr) spectroscopy has been used to study the ionization state of the sulfonamide, 4'-sulfamylphenyl-2-azo-7-acetamido-1-hydroxynaphthalene-3,-6-disulfonate (neoprontosil), bound to carbonic anhydrase. the correlation of effects of ph and deuteration on the spectra of model compounds with these effects on the neoprotosil spectrum allows us to assign spectral bands in the 900-1000 and 100-1200 cm-1 regions to the so2nh2 group. large shifts in these bands occur upon ionization of th ... | 1977 | 13824 |
| rabies glycoprotein purification by isoelectric focusing (author's transl). | a glycoprotein was extracted with triton x100 from rabies virus grown in primary foetal bovine kidney cells. this glycoprotein was further purified by iso electro focusing and showed a major peak at ph 7,0 and a smaller peak at ph 4,6. purified fractions were migrated on polyacrylamide gels and assayed for immunogenicity. | 1976 | 14578 |
| energy-linked protonation of quinacrine in beef heart submitochondrial membranes. | 1. the absorption spectrum of quinacrine in aqueous solution, in the visible region, changes with the ph of the medium in the ph range from 6.0 to 9.0 with an isosbestic point at 353 nm. this indicates that the monoprotonated (quinacrine - h+) and the diprotonated (quinacrine - 2h+) forms of quinacrine at equilibrium in this ph range have a 1 to 1 stoichiometry. 2. the monoprotonated and the dipronated forms to quinacrine exhibit similar fluorescence emission spectra, but distinctive fluorescenc ... | 1977 | 13828 |
| calf thymus alkaline phosphatase. i. properties of the membrane-bound enzyme. | a membrane fraction from calf thymocytes was used to investigate molecular and catalytic properties of membrane-bound alkaline phosphatase (ortho-phosphoric-monoester phosphohydrolase ec 3.1.3.1). the principal findings were: 1. solubilization of membranes with the non-ionic detergent triton x-100 increases alkaline phosphatase activity by 30-40%. the enzyme activity elutes in a single peak (stokes' radius = 7.7 nm) after chromatography in sepharose 6b in the presence of triton x-100. the activi ... | 1977 | 13842 |
| benzamidine as an inhibitor of proacrosin activation in bull sperm. | epididymal and ejaculated sperm contain a zymogen form of acrosin (acrosomal proteinase, ec 3.4.21.10) which is converted to active enzyme prior to fertilization. benzamidine at concentrations greater than 10 mm has been shown to inhibit the conversion of proacrosin to acrosin. based on this inhibition, a procedure was developed for extracting and quantitating the proacrosin content of bull sperm. sperm were isolated from semen and washed by centrifugation through 1.3 m sucrose and the outer acr ... | 1977 | 13845 |
| iodination-deiodination. a radiochemical method for detection of structure and changes in structure in rna. | bound iodine is released from radioiodinated nucleotides in polymers exposed to sodium bisulfite. the rate of bisulfite-catalyzed deiodination of pyrimidines can be controlled both by change of temperature of ph and is also dependent on the molecular association of the nucleotide. the rate of release of iodine from iodocytidine in polycytidylate is greater than the rate of elimination from rna. experiments testing the influence of base-pairing of the iodopyrimidines in synthetic polynucleotides ... | 1977 | 14687 |
| the binding of calcium to bovine fibrinogen. | the determination of the number of calcium binding sites of fibrinogen was carried out by means of equilibrium experiments. at ph 7.5 fibrinogen has 3 binding sites of high affinity and several binding sites of low affinity. in the presence of mgcl2 (10(-2)m) the sites of low affinity are eliminated, suggesting that they are not specific and due to weak interactions. study of the effect of the ph have demonstrated that the 3 sites of high affinity are not identical. at ph values below 7.5 one si ... | 1977 | 13854 |
| the gamma-carboxy glutamic acid content of human and bovine prothrombin following warfarin treatment. | a form of prothrombin induced by warfarin therapy, has been isolated which is adsorbed onto insoluble barium salts, but has a reduced biological activity. this protein contains, on average, seven out of a possible ten gamma-carboxy glutamic acid residues. a second form of prothrombin is also described, which is not adsorbed into barium slats, and has less than 1% the activity of the normal protein, contains only four gamma-carboxy glutamic acid residues. the significance of these results is disc ... | 1977 | 13857 |
| hydroxylation of dehydroepiandrosterone in the eye lens. | hydroxylation of the steroid hormone dehydroepiandrosterone in the calf lens is inhibited by carbon monoxide and stimulated by nadph. the enzyme concerned was found to be membrane-bound. although the enzyme resembles the liver mono-oxygenase system in these characteristics, the presence of cytochrome p-450 in the lens could not be proved by measuring a difference spectrum with carbon monoxide, probably because the concentration of the enzyme is too low. preparations of purified lens fiber plasma ... | 1977 | 13865 |
| inactivation of mitochondrial 2-oxoglutarate dehydrogenase complex as a result of phospholipid degradation induced by freeze-thawing. | the inactivation of 2-oxoglutarate dehydrogenase complex by freeze-thawing was examined along with alterations of membrane phospholipids, in order to elucidate the mechanism of freezing injury in mitochondria. the dehydrogenase complex activity in slowly frozen and thawed mitochondria decreased to 70% as compared to intact mitochondria and further decreased during incubation. this inactivation during incubation was temperature dependent, i.e., at temperatures up to 25 degrees c there was a sligh ... | 1977 | 13867 |
| characterization and substrate specificity of fumarylacetoacetate fumarylhydrolase. | the molecular weight of fumarylacetoacetate fumarylhydrolase (ec 3.7.1.2) is 86 000 +/- 10 000, as determined by gel filtration. the enzyme appears to be a dimer with a monomer molecular weight of 38 000 - 43 000, as determined by gel electrophoresis, gel filtration in guanidine-hydrochloride, and ultracentrifugation. the subunits appear to be identical, as only one band is seen in gel electrophoresis, only one protein peak is detected in gel filtration in guanidine-hydrochloride, and only one a ... | 1977 | 13916 |
| amino acid composition of casein isolated from the milks of different species. | | 1977 | 13923 |
| a chromatin-bound proteolytic activity with unique specificity for histone h2a. | a protease associated with purified calf thymus chromatin has been found to act exclusively upon histone h2a, yielding a single new protein species, ch2a. this fragment migrates faster than h2a in acrylamide gel electrophoresis under denaturing conditions. the ch2a was purified and subjected to amino acid analysis and partial sequencing by the use of carboxypeptidase a. these studies demonstrated that ch2a had been derived from the removal of fifteen amino acids from the carboxy-terminal end of ... | 1976 | 13934 |
| perfused lung preparation for studying altered gaseous environments. | an isolated perfused lung (ipl) preparation was used to investigate the influence of acute environmental stress on lung substrate metabolism. the ipl apparatus consists of four perfusion flasks housed in a temperature-controlled lucite box with a circulation fan. lungs are ventilated by a positive pressure ventilation pump. the ventilation is arranged so that the lung can be ventilated with any desired gas composition with concomitant collection of expired gases. the perfusion medium is circulat ... | 1976 | 13988 |
| artificial energy conservation in the respiratory chain. no native coupling site between cytochrome c and oxygen. | | 1977 | 14030 |
| subcellular distribution of pyridoxal kinase in ox retina. | pl kinase activity has been determined in primary and secondary subcellular fractions of ox retina. enzymic activity is predominantly located in the soluble fraction (s3). about 65% of the recovered pl kinase activity of crude mitochondria is released from synaptosomal fraction after hypoosmotic treatment. pl kinase activity in supernatant fraction (s3) does not exceed the enzyme activity measured in the homogenate, excluding the presence of a particulate-bound inhibitor to pl kinase in the homo ... | 1976 | 14904 |
| reaction of bovine and equine growth hormones with tetranitromethane. | bovine and equine growth hormones were chemically modified with tetranitromethane, at ph 7.4 during 5 h and at ph 8.0 in the presence of 8 m urea during 1 h. a) both hormones have very similar but not identical reactivities. b) the nitration of the reactive tyrosines and tryptophan residues at ph 7.4 produces no detectable changes in their immunological or somatotrophic activities. c) the nitration of all tyrosine residues in both hormones gives rise to a complete loss of somatographic activity ... | 1977 | 14079 |
| binding of tritiated bovine parathyroid hormone to plasma membranes from bovine kidney cortex. | a membrane fraction enriched in parathyroid hormone (pth)-sensitive adenylate cyclase and sodium and potassium ion-activated (na+, k+)-atpase was prepared from bovine kidney. tritiated pth binding to this membrane fraction was dependent on both hormone and membrane protein concentration. both total and specific binding of the hormone decreased significantly after 5 to 10 min of incubation at 22 degrees. pth binding was highly specific, being sensitive to inhibition only with active forms of unla ... | 1977 | 14129 |
| studies of binding of parathyroid hormone to a detergent-dispersed preparation from bovine kidney cortex plasma membranes. | bovine kidney plasma membranes containing parathyroid hormone-sensitive adenylate cyclase activity were dispersed with 1% triton x-100 and centrifuged at 150,000 x g for 2 h. approximately 40% of the total membrane protein was extracted by this procedure. the extraction greatly reduces the fluoride-stimulated and the parathyroid hormone-sensitive adenylate cyclase activity of the membranes and yields a supernatnat which binds biologically active, tritiated parathyroid hormone. hormone binding is ... | 1977 | 14130 |
| phosphorylation of cardiac troponin by cyclic adenosine 3':5'-monophosphate-dependent protein kinase. | the purpose of this investigation was to characterize the phosphorylation of bovine cardiac troponin by cyclic amp-dependent protein kinase. the purified troponin-tropomyosin complex from beef heart contained 0.78 +/- 0.15 mol of phosphate per mol of protein. analysis of the isolated protein components indicated that the endogenous phosphate was predominately in the inhibitory subunit (tn-i) and the tropomyosin-binding subunit (tn-t) of troponin. when cardiac troponin or the troponin-tropomyosin ... | 1977 | 14136 |
| economics of protecting cattle from mosquito attack relative to injury thresholds. | | 1977 | 14179 |
| pharmacology and biochemistry of haloperidol. | | 1976 | 14331 |
| an improved technique for the preparation of chromosomes from cattle whole blood. | the method of preparation of chromosomes from cattle whole blood is described in detail and has been tested by use on more than 1000 different animal samples. it is shown that elevated levels of glutamine and 1-cystine increase the mitotic index and improve the keeping qualities of the medium 199. the recipe for whole medium is modified, describing the inclusion of heparin for the first time and recommending the exclusion of fetal calf serum. the optimum ph 7-3 is confirmed. the reported conditi ... | 1977 | 14362 |
| soluble fibrin complexes: separation as a function of ph and characterization. | 1. the influence of the ph on the separation of high molecular weight derivatives obtained by a limited action of thrombin on fibrinogen was studied by agarose gel chromatography. when the ph of the elution buffer was 8.5, non crosslinked associations were easily separated in two peaks eluted prior to the fibrinogen peak: one contained a dimer, the other several high polymers. at ph 6.5, only the fibrinogen peak appeared: the fibrinogen molecule proteolysed by thrombin formed no stable associati ... | 1977 | 14416 |
| bovine hypocuprosis. | | 1977 | 14435 |
| hypothalamic mechanisms transforming nervous information into humoral information. | | 1976 | 14479 |
| pigment formation by trichophyton rubrum: differentiation between t. rubrum and t. mentagrophytes on serum albumin agar (author's transl). | on serum albumin agar (bovine albumin) with initial ph-values of 5.0-6.0, trichophyton rubrum showed a yellow pigmentation, and on the same medium with an initial ph-value of 7.0, a red pigmentation. strains of trichophyton mentagrophytes have never shown pigmentation until now, the scarce growth (submerged) of t. rubrum on serum albumin agar is associated with a pigment formation that may be used for diagnostic purposes. it could be read within 3-7 days. serum albumin agar with the initial ph-v ... | 1977 | 15390 |
| spin-labeling studies of beef-liver glutamate dehydrogenase. | | 1977 | 14634 |
| active proton uptake by chromaffin granules: observation by amine distribution and phosphorus-31 nuclear magnetic resonance techniques. | the hydrogen ion activity within isolated chromaffin granules can be estimated from the distribution of the weak base methylamine and from phosphorus-31 nuclear magnetic resonance spectra of atp contained in the granules. following the addition of atp to the external medium, the internal ph drops by 0.2 to 0.5 unit. this change occurs only in medium containing a permeant anion such as chloride and is abolished by an uncoupler of oxidative phosphorylation. these results indicate that the chromaff ... | 1977 | 14667 |
| light-activated calcium release from sonicated bovine retinal rod outer segment disks. | calcium trapped within sonicated and resealed bovine rod outer segment disks is released upon light exposure with a stoichiometry of 0.75 +/- 0.05 calcium for each rhodopsin bleached. the amount of calcium liberated is proportional to the amount of bleaching in the range of 20 to 100% bleaching and is relatively insensitive to the internal trapped calcium concentration. the results are obtained using a flow system in which the disk membrane vesicles are adsorbed on glass particle supported by a ... | 1977 | 14680 |
| modification of amino acids and bovine pancreatic ribonuclease a by kethoxal. | kethoxal (3-ethoxy-2-ketobutanal) reacts with the guanidino group of nalpha-acetylarginine to produce four derivatives, reactive to periodate, stable at ph 7, with 15% reverting to arginine on acid hydrolysis. other amino acids with blocked alpha-amino groups do not react, except the epsilon-amino of lysine (slowly). the pk of the mixed kethoxal-nalpha-acetylarginine derivatives is 5.8-6.1. kethoxal reacts at neutral ph with arginyl residues of bovine pancreatic ribonuclease a. in the presence o ... | 1977 | 14699 |
| low ph stability of alpha-1-antititrypsin. | according to the previous findings of others, the trypsin inhibitory capacity of alpha-1-antitrypsin is irreversibly lost in acidic solutions below ph 5.0. in contrast, experiments reported herein show that considerable inhibitory activity can be regenerated as a time-dependent phenomena following titration to basic media. the rate of recovery of activity is accompanied by a decreasing amplitude in the fluorescent emission spectrum at 335 nm of acidified alpha-1-antitrypsin solutions following a ... | 1977 | 14700 |
| electron spin relaxation time of fe(iii) in high spin heme proteins. | the electron spin relaxation time of high spin fe(iii), taus, was determined from the frequency dependence (5-100 mhz) of the longitudinal proton relaxation rates of water in solutions of catalase, metmyoglobin and acid ferricytochrome c. in all three high-spin heme proteins the relaxation rates incrased below 25 mhz, while no frequency dependence was observed above that frequency. the results are interpreted by assuming that taus, which modulates the dipolar interaction between the unpaired ele ... | 1977 | 14708 |
| protease from bovine spleen with kininogenase activity. | a protease with kininogenase activity at ph 7.5 was isolated from bovine spleen extract by gel filtration and ion exchange chromatography. the protease was found in the fraction with molecular weight lower than 25.000 and was separated from the other neutral sh-dependent protease by chromatography on km-cellulose. the kininogenase activity was inhibited by dfp and trasylol; soybean trypsin inhibitor had no effect. the protease did not split n-benzoyl-l-arginine ethyl ester and n-benzoyl-d, l-arg ... | 1976 | 14722 |
| indication of the metarhodopsin i-ii transition by absorption-changes of eriochromblack t. | the dye eriochromblack t (erio t), added to an aqueous suspension of bovine retinal outer segments solubilized by digitonin, shows a light-induced absorption-increase at lambda = 645 nm. erio t is shown to directly interact with miscellar metarhodopsin i and metarhodopsin ii. the absorption-changes of erio t can be regarded as an indication of the transition from the metarhodopsin i conformation (with associated ca2+) to the metarhodopsin ii conformation (with associated h+). | 1977 | 14740 |
| nonporous magnetic materials as enzyme supports: studies with immobilized chymotrypsin. | chymotrypsin has been immobilized to several nonporous magnetic materials. nickel particles were considered to be most suitable as immobilized enzyme supports. chymotrypsin immobilized to nonporous magnetic supports was not fouled significantly by either whole milk or clarified yeast homogenate. ae-cellulose-chymotrypsin was rapidly fouled by both these materials and chymotrypsin immobilized to acrylic-based ion exchangers was slowly fouled. immobilized enzyme activity was found to be inversely ... | 1977 | 14743 |
| purification and properties of glutathione synthetase from bovine lens. | | 1977 | 14840 |
| bacteriostatic effect of human milk and bovine colostrum on escherichia coli: importance of bicarbonate. | at ph 7.4 and in the presence of nahco3, human milk and bovine colostrum inhibited the growth of escherichia coli o111. adding sufficient iron to saturate the iron-binding capacity of the lactoferrin present in the milk or colostrum prevented bacteriostasis. at ph 6.8 neither molk nor colostrum inhibited e. coli 0111. adjusting the ph to 7.4 with nahco3 resulted in the development of bacteriostatic activity. adjusting the ph to 7.4 with naoh was ineffective. dialyzed colostrum and milk inhibited ... | 1977 | 14890 |
| the acylation of bovine serum albumin with diacetylcycloserine. | the reaction of the amino groups of bovine serum albumin (bsa) with diacetylcycloserine (i) at ph 7.2-9.0 proceeded with both acylation by the diacetyl-beta-aminooxy-d-alanyl (daa) group and acetylation. the number of daa groups was determined by their conversion to cycloserine (iii) which can be accurately measured in micromolar amounts. the method was developed using the model compound diacetyl-beta-aminooxy-d-alanine butyl amide (ii) which was converted to beta-aminooxy-d-alanine butyl amide ... | 1977 | 14899 |
| kinetic studies on the adp-atp exchange reaction catalyzed by na+, k+-dependent atpase. evidence for the k.s.t. mechanism with two enzyme-atp complexes and two phosphorylated intermediates of high-energy type. | the kinetic properties of the 3hadp-atp exchange reaction catalyzed by na+, k+-dependent atpase ec 3.6.1,3 were investigated, using nai-treated microsomes from bovine brain, and the following results were obtained. 1. the rates of the na+-dependent exchange reaction in the steady state were measured in a solution containing 45 micronm free mg2+, 100 mmnacl, 80 micronm atp, and 160 micronm adp at ph 6.5 and 4-5 degrees. the rate and amount of decrease in phosphorylated intermediate on adding adp, ... | 1977 | 14933 |
| kallikrein inhibitors in rat plasma. | the kallikrein inhibitor contents of human and animal plasma were determined with glandular kallikreins ec 3.4.21.8. one ml of plasma could inactivate 20-700 kallikrein units (ku). rat plasma was the most potent and inactivated 230-700 ku. however, no enzyme capable of inactivating kallikrein could be found in this plasma. two fractions which inhibited hog pancreatic kallikrein, a fraction corresponding to alpha2-macroglobulin and a fraction which was eluted prior to albumin, were separated from ... | 1977 | 14935 |
| dependence of the proton redox pup ph on mitochondria. | | 1976 | 15579 |
| molecular architecture of cytochrome oxidase and its transition on treatment with alkali or sodium dodecyl sulfate. | in dimeric cytochrome oxidase ec 1.9.3.1, one of the two heme a molecules of one monomeric unit has been proposed to be converted by the other unit, thus becoming latent in terms of catalytic functions (1). as the dimer was split into two monomers by treatment with alkali or sodium dodecyl sulfate (sds), it was shown that the intensity of circular dichroism (cd) in the soret region due to heme a decreased, probably reflecting release of the strain on the latent heme. on the other hand, the profi ... | 1977 | 14953 |
| effect of aspartate on complexes between glutamate dehydrogenase and various aminotransferases. | in previous studies it was found that: (a) aspartate aminotransferase increases the aspartate dehydrogenase activity of glutamate dehydrogenase; (b) the pyridoxamine-p form of this aminotransferase can form an enzyme-enzyme complex with glutamate dehydrogenase; and (c) the pyridoxamine-p form can be dehydrogenated to the pyridoxal-p form by glutamate dehydrogenase. it was therefore concluded (fahien, l.a., and smith, s.e. (1974) j. biol. chem 249, 2696-2703) that in the aspartate dehydrogenase r ... | 1977 | 14147 |
| enzymic oxidation of 3-hydroxyxanthine to 3-hydroxyuric acid. | 1. bovine milk xanthine oxidase (xanthine:oxygen oxidoreductase, ec 1.2.3.2) oxidises 3-hydroxyxanthine slowly to 3-hydroxyuric acid; the 1-methyl derivative of 3-hydroxyxanthine is attacked about twice as fast. 2. the ph optimum for the reaction of 2-hydroxyxanthine is near 5, i.e. the neutral form of this substrate is attacked much faster than the anion. probably in the "active" form of the latter, the negative charge is located mainly in the imidazole ring, thus inhibiting nucleophilic attack ... | 1977 | 15604 |
| the transient-state kinetics of l-glutamate dehydrogenase. ph-dependence of the burst rate parameters. | the ph dependence of the initial transient velocity of nadph production during the burst phase of the oxidative deamination of l-glutamate by l-glutamate dehydrogenase (l-glutamate : nad(p)+ oxidoreductase (deaminating), ec 1.4.1.3) and nadp+ has been measured by stopped-flow spectrophotometry. these studies provide evidence that the entire ph dependence below ph 8.26 arises from reaction steps contributing to v of the burst with an apparent pka of 8.1 +/- 0.1. the data are consistent with a mod ... | 1977 | 15605 |
| seminal quality, spermatozoal outpost, and testicular changes in growing holstein bulls. | nine holstein bulls, initially between the ages of 17 and 22 mo, awaiting proofs in artificial breeding, were ejaculated each summer for 3 yr, and 8 and 7 survivors for 4 and 5 yr, respectively, to study changes in the same group of bulls and determine the predictive value of early measurements. semen was collected twice a day, 2 days per wk, for 4 wk. bulls differed in testicular size, consistency, ejaculate volume, total spermatozoal output, percentage of unstained spermatozoa and abnormal spe ... | 1977 | 14176 |
| dehydrogenase and transhydrogenase properties of the soluble nadh dehydrogenase of bovine heart mitochondria. | the soluble nadh dehydrogenase of low molecular weight, isolated from complex i (nadh:ubiquinone oxidoreductase, ec 1.6.5.3) of the respiratory chain, has been shown to have nadph dehydrogenase and nadph leads to nad transhydrogenase activities. both activities are greatly increased in the presence of added guanidine-hcl and at ph values less than 6.5. the chromophores of the soluble enzyme (flavin and iron--sulfur centers) are reduced by nadh and nadph to the same extent. the latter reduction i ... | 1977 | 15255 |
| a proton magnetic relaxation study of ferric myoglobin and haemoglobin in water/ethanediol solutions. | structural alterations of the haem vicinity of the high-spin derivatives of bovine ferric myoglobin (metmyoglobin) and human haemoglobin and the changes of the interaction with inositol hexaphosphate induced by ethanediol were monitored by solvent-proton magnetic relaxation. on addition of ethanediol up to 60% the fluoromet derivatives exhibit a gradual increase in the accessibility of the haem for the molecules from the solvent. in aquomethaemoglobin solutions with more than 25% ethanediol ther ... | 1977 | 15623 |
| modulation of protein phosphorylation by a factor purified from adipocytes. | 1. a factor which modulates the activity of cyclic amp-dependent protein kinase copurifies from rat adipocytes with an inhibitor of adenylate cyclase. purification and stability studies suggest that both effects reside in a single factor previously referred to as a feedback regulator. 2. the magnitude and direction of the feedback regulator effect on cyclic amp-dependent protein kinase activity was dependent on the concentration of feedback regulator and the concentration and type of protein sub ... | 1977 | 15626 |
| detection in bovine adrenal cortex of a lipoidal substance that yields pregnenolone upon treatment with alkali. | bovine adrenal cortical tissue contains a lipoidal derivative of pregnenolone (3beta-hydroxy-pregn-5-en-20-one) from which the free steroid can be liberated by treatment with alkali. evidence for the presence of such an entity comes from examination of a nonpolar extract of tissue from which pregnenolone and its sulfate had been removed by chromatography. treatment of the nonpolar fraction with alkali followed by exhaustive chromatographic analysis led to the detection of pregnenolone. the stero ... | 1977 | 15261 |
| studies on membrane receptor sites for serotonin in the brain. | the competitive effect of 5,6-dihydroxytryptamine, morphine and chlorpromazine on the binding of serotonin (5-ht) to rat brain slices was investigated. ths busynaptosomal localization of the binding of morphine in bovine midbrain preparations was compared to that of 5-ht and found to be considerably higher. the condensation of 5-ht and tryptamine receptor carbonyl groups in brain with phenylisopropylhydrazine was shown in vitro and vivo. membrane particles labeled with 14c tryptamine or 5-ht in ... | 1977 | 15304 |
| anoestrus in cattle. | | 1977 | 15343 |
| salazopyridazine with vitamins a and d in gastrointestinal diseases in calves. | | 1976 | 15344 |
| a role for cyclic nucleotides and protein kinase in vertebrate photoreception. | | 1976 | 15423 |
| a simple method for determination of pepsinogen in bovine serum and plasma. | | 1977 | 15428 |
| effect of feeding frequency on fermentation pattern and microbial activity in the bovine rumen. | | 1977 | 15429 |
| fermentation pattern in the bovine rumen after feeding straight feeds. | | 1977 | 15431 |
| microimmunodiffusion test for detection of antibodies to infectious bovine rhinotracheitis virus in bovine serum. | a microimmunodiffusion test (midt) specific for detection of antibodies to infectious bovine rhinotracheitis (ibr) in bovine serum has been developed. the antigen used in the midt was prepared from ibr virus-infected madin-darby bovine kidney cells grown in tissue culture. the antigen was stable, and relatively high yields were obtained readily. results of the midt were obtained within 48 hours and agreed with those of the serum-neutralization test. | 1977 | 15490 |
| gastrointestinal motility in the ruminant: influence of the nature of feed. | | 1976 | 15493 |
| natural antiallergenic factors in bile. | two groups of substances having an antihistaminic activity were found on purifying bovine bile. it has already been found that bile acids inhibit contraction of guinea pig ileum; another principle has been isolated which is one thousand times more active than the bile acids; this (these) substance(s)--san (" substance antiallergique naturelle ")--seems to have more inhibitory effect on smooth muscle contraction induced by srsa than histamine, acetylcholine, bradikinin and serotonin. san is also ... | 1977 | 15496 |
| a pulse-radiolysis study of the catalytic mechanism of the iron-containing superoxide dismutase from photobacterium leiognathi. | the mechanism of the enzymic reaction of an iron-containing superoxide dismutase purified from the marine bacterium photobacterium leiognathi was studied by using pulse radiolysis. measurements of activity were done with two different preparations of enzyme containing either 1.6 or 1.15 g-atom of iron/mol. in both cases, identical values of the second-order rate constant for reaction between superoxide dismutase and the superoxide ion in the ph range 6.2-9.0 (k=5.5 x 10(8) m-1-s-1 at ph 8.0) wer ... | 1977 | 15540 |
| guanosine cyclic monophosphate-dependent protein kinase from foetal calf heart. purification, general properties and catalytic subunit. | cyclic gmp-dependent protein kinase was purified from foetal calf hearts, and its general properties and subunit structure were studied. the enzyme was purified over 900-fold from the heart extract by ph 5.3-isoelectric precipitation, deae-cellulose chromatography, sephadex g-200 filtration and hydroxyapatite treatment. the purified myocardial enzyme, free from cyclic amp-dependent protein kinase contamination, exhibited an absolute requirement of stimulatory modulator (or crude modulator contai ... | 1977 | 15543 |
| isolation and characterization of sheep pepsin. | sheep pepsin was isolated (approx. 120-fold purification) from aqueous abomasal homogenates by (1) ph fractionation, (2) chromatography on sepharose 4b-poly-l-lysine columns and (3) gel filtration on sephadex g-100. the enzyme had mol.wt. approx. 34000, n-terminal valine and c-terminal alanine. the amino acid composition of sheep pepsin was generally similar to that of pig and ox pepsins, with a very low content of basic residues and a high content of acidic and hydroxy-amino acids. the ph optim ... | 1977 | 15546 |
| properties of rat liver microsomal stearoyl-coenzyme a desaturase. | 1. rat liver microsomal stearoyl-coa desaturase activity was shown to be stimulated by both bovine serum albumin and a basic cytoplasmic protein from rat liver. 2. partially purified desaturase is unaffected by either of these two proteins. 3. bovine serum albumin appears to exert its effect on the crude system by protecting the desaturase substrate, stearoly-coa, from the action of endogenous thiolesterases. 4. by using partially purified enzyme preparations, it was possible to establish the su ... | 1977 | 15547 |
| the isolation and partial characterization of the major glycoprotein (lgp-i) from the articular lubricating fraction from bovine synovial fluid. | the articular lubricating fraction from bovine synovial fluid was prepared by repeated fractionation in three consecutive cscl density gradients to remove completely traces of hyaluronic acid. the major glycoprotein consituent (lgp-i) was then isolated by repeated gel-permeation chromatography. the yield of the lgp-i component was about 20 mg/litre of synovial fluid. sedimentation-equilibrium measurements showed that this glycoprotein was homogeneous and the mol.wt. was calculated to be 227500. ... | 1977 | 15548 |
| large fragments of human serum albumin. | large fragments of human serum albumin were produced by treatment of the native protein with pepsin at ph3.5. published sequences of human albumin behrens, spiekerman & brown (1975) fed. proc. fed. am. soc. exp. biol. 34, 591; meloun, moravek & kostka (1975) febslett.58, 134-137were used to locate the fragments in the primary structure. the fragments support both the sequence and proposed disulphide-linkage pattern (behrens et al., 1975). as the ph of a solution of albumin is lowered from ph4 to ... | 1977 | 15551 |
| action of lipophilic cations on the protonic conduction in the internal mitochondrial membrane. | | 1976 | 15578 |
| pathways of silicomolybdate photoreduction and associated photophosphorylation in tobacco chloroplasts. | three sites of silicomolybdate reduction in the electron transport chain of isolated tobacco chloroplasts are described. the relative participation of these sites is greatly influenced by the particular reaction conditions. one site (the only site when the reaction medium contains high concentrations of bovine serum albumin (greater than 5 mg/ml) is associated with photosystem i, since it supports phosphorylation with a p/e2 value close to 1 and the reaction is totally sensitive to both plastocy ... | 1977 | 15593 |
| studies on the intestinal absorption of bovine xanthine oxidase. | | 1977 | 16272 |
| adenine nucleotide transport in sonic submitochondrial particles. kinetic properties and binding of specific inhibitors. | 1. a procedure for preparation of sonic submitochondrial particles competent for adenine nucleotide transport is described. adp or atp transport was assayed, in the presence of oligomycin, in a saline medium made of 0.125 m kcl, 1 mm edta, 10 mm 4-morpholinopropane sulfonic acid buffer, ph 6.5. 2. sonic particles transport adp and atp by an exchange diffusion process. externally added adp (or atp) is exchanged with internal adp and atp with a stoichiometry of one to one. the v value for adp tran ... | 1977 | 15594 |
| determination of the effective concentration of jodonal a for the disinfection of the skin and teats after milking. | the bactericidal effectivity of jodonal a in 1:10, 1:5, and 1:3 solutions was tested on human skin and on the teats of cow mammary glands. the 1:3 dilution ratio proved best for three-minute exposure. jodonal a used in this concentration in 522 cows for the post-milking disinfection of teats for 10 months exerted no harmful effect on the skin of the mammary glands. | 1976 | 16377 |
| stimulation of guanylate cyclase by sodium nitroprusside, nitroglycerin and nitric oxide in various tissue preparations and comparison to the effects of sodium azide and hydroxylamine. | sodium nitroprusside, nitroglycerin, sodium azide and hydroxylamine increased guanylate cyclase activity in particulate and/or soluble preparations from various tissues. while sodium nitroprusside increased guanylate cyclase activity in most of the preparations examined, the effects of sodium azide, hydroxylamine and nitroglycerin were tissue specific. nitroglycerin and hydroxylamine were also less potent. neither the protein activator factor nor catalase which is required for sodium azide effec ... | 1977 | 14978 |
| cathepsin d activity in bovine articular cartilage, synovial membrane and fluid: degradation of cartilage proteoglycans from same joint. | cathepsin d type proteases were extracted from articular cartilage, synovial membrane, and synovial fluid from normal, adult bovine knee joints. a sensitive enzyme assay made it possible to measure protease activity in the different tissues from individual joints. highest activity was found in the synovial membrane, while cell free synovial fluids contained comparatively low activity. the degrading effect on articular cartilage proteoglycans (pgc and pgs), isolated from the same joints, was demo ... | 1976 | 15110 |
| on the enzymatic breakdown of tripolyphosphate and diphosphate in minced meat. v. change in the diphosphatase activity of muscle post mortem (author's transl). | the diphosphatase (dpase) activity of minced bovine muscle decreased during storage of the intact muscle post mortem (p.m.) but there was only little change after development of rigor mortis. the drop in ph p.m. seems to be not the only reason for the decrease in dpase activity. in the postrigor muscle the dpase activity, measured at ph greater than 6, increased during the breakdown of dp. the rise of activity was the slower the longer the muscle was stored. the result of a mathematical regressi ... | 1977 | 16412 |
| on the enzymatic breakdown of tripolyphosphate and diphosphate in minced meat. vi. influence of ph on the tripolyphosphatase and diphosphatase activities in bovine muscle (author's transl). | the ph optimum of the tripolyphosphatase activity of minced bovine muscle post rigor was 5.6. the ph optimum of the diphosphatase activity was in the range between ph 6.7 and 6.8. the prolonged influence of ph values around 7 caused an additional increase in the diphosphatase activity. | 1977 | 16413 |
| a d-amino acid oxidase from chlorella vulgaris. | a procedure has been developed for the partial purification from chlorella vulgaris of an enzyme which catalyzes the formation of hcn from d-histidine when supplemented with peroxidase of a metal with redox properties. some properties of the enzyme are described. evidence is presented that the catalytic activity for hcn formation is associated with a capacity for catalyzing the oxidation of a wide variety of d-amino acids. with d-leucine, the best substrate for o2 consumption, 1 mol of ammonia i ... | 1977 | 15607 |
| an inactive renin in human plasma. | normal human plasma contains an active form of renin that is activated by acidification to ph 3.0 and comprises 56% of the total renin. in our study, inactive renin was also present in plasma from five anephric persons, and the proportion of active to inactive renin in these subjects was similar to normal. plasma from normal pregnant women contained increased concentrations of inactive renin and the proportion of inactive renin was raised to around 66%. plasma from persons with renal hypertensio ... | 1977 | 15736 |
| purification of bovine thyroid peroxidase. | trypsin-solubilized peroxidase activity from beef subcellular particles was resolved by deae-cellulose chromatography into 5 fractions, which contained enzymatically active components that ranged in molecular size from 73,000 to 340,000 daltons. the most active fraction (mol wt, 92,000 by gel filtration) was further purified (59,000-fold overall) by chromatography on hydroxylapatite. this highly purified peroxidase preparation had an absorbance purity ratio (a410:a280) of 0.55 and oxidized iodid ... | 1977 | 15822 |
| beta-adrenergic stimulation of cyclic amp content and parathyroid hormone release from isolated bovine parathyroid cells. | the effects of beta-adrenergic agonists and antagonists on cyclic amp (camp) accumulation and parathyroid hormone (pth) release from isolated bovine parathyroid cells have been determined. beta-adrenergic agonists markedly stimulate camp production and pth release with an order of potency (-) isoproterenol greater than (-)epinephrine greater than greater than (-) norepinephrine, suggesting a beta2-type adrenergically mediated process. both effects are blocked by the beta-blocker propranolol with ... | 1977 | 15823 |
| influence of reagent quality and reaction conditions on the determination of serum albumin by the bromcresol green dye-binding method. | in an age of reference methodologies and sophisticated quality control techniques it is surprising that so little attention is paid to the quality of the reagents that are used. this paper reports on an investigation of the bromcresol green dye-binding procedure for the estimation of serum albumin in which particular attention has been paid to changes in the reagent components that contribute to the performance of the method. it has been shown that detailed attention to the quality control of th ... | 1977 | 16554 |
| effect of imidazoles and ph on aging of phosphylated acetylcholinesterase. | | 1977 | 16611 |
| binding of organic ions by proteins--1. interaction of 1-benzyl-3-indazoleoxyacetate with serum albumin. | | 1977 | 16612 |
| direct identification of beta-adrenergic receptors on isolated bovine parathyroid cells. | the radioiodinated beta-blocker iodohydroxybenzylpindolol (125ihyp) has been used to identify directly and characterize beta-adrenergic receptors in isolated bovine parathyroid cells. 125ihyp was bound rapidly and reversibly to isolated bovine parathyroid cell membranes. scatchard analysis revealed a single class of binding sites with high affinity (4 x 10(10m-1) and low capacity (0.7 pmol/mg). saturation analysis of 125ihyp binding to intact bovine parathyroid cells suggested a site with simila ... | 1977 | 15824 |
| estimation of pregnenolone synthesis in rat adrenal homogenates: some cofactor requirements: effects of stress, hypophysectomy, cortisone and acth. | pregnenolone synthesis was estimated in whole adrenal homogenates incubated in the presence of cyanoketone (2alpha-cyano-4,4,17alpha-trimethyl-androst-5-en-17beta-ol-3-one). the yield of pregnenolone depended on the type of incubation medium employed. both ca++ and bovine serum albumin (bsa) markedly stimulated the rate of pregnenolone synthesis as did nadph or nadph generating system. aminoglutethimide added in vitro inhibited cholesterol sidechain cleavage activity. ether stress in vivo stimu ... | 1977 | 15826 |