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The extracellular beta-glucosidase of Trichoderma viride generally is present in low levels when the organism is cultured on cellulose because it is inactivated under the acid conditions which develop in the medium while the other enzymes of the cellulase complex are more stable. With the appropriate pH control, inacti... |
Fusarium moniliforme was cultured semicontinuously on a carob medium in a 14-liter fermentor (8.5-liter working volume). The growth medium provided 2.4% carob sugar, 0.72% NH4H2PO4, and 0.03% MgSO4-7H2O. The biomass harvest was 8.8 g/liter per day. Ninety percent of the sugars were consumed, and the pH dropped from 5.9... |
A Put mutant of Serratia marcescens, deficient in proline oxidase and therefore unable to degrade proline, was used to assay for an enzymatic reaction responsible for incorporation of proline into prodigiosin. The reaction had a pH optimum of 7.5 and a Km of 1.1 X 10(-4) M at 27 C. At temperatures above 27 C, the veloc... |
A cell-free extract, prepared from Aspergillus parasiticus ATCC 15517 grown in synthetic medium, was active in converting [14C]sterigmatocystin into aflatoxin B1 in the presence of reduced nicotinamide adenine dinucleotide phosphate. The activity was demonstrated by the time course of conversion and the linear dependen... |
gamma Glutamyl transpeptidase (GGT) activity was measured in normal neonates and in maternal serum post partum. Levels were above the normal adult range (35I U/1) in all neonates and a significant correlation was bound between enzyme activity and bilirubin levels on day 7(P less than 0-005). The mean bilirubin level on... |
Milk feeds were given through indwelling nasogastric tubes to 14 infants with respiratory distress. Similar cardiorespiratory disturbances were observed when the infants were fed (5 ml/kg per feed) human milk, cow's mild, or distilled water. Pao2 fell after a feed but recovered to the prefeed value at 30 minutes, at w... |
A simple, inexpensive, highly efficient disposable membrane oxygenator with low priming volume and a microporous membrane recently has become available. Animal and clinical investigations of its use have been most satisfactory, and clinical experience now has been extended to include 285 patients. Its primary advantage... |
In 12 rabbits hypothermia and rewarming were induced with temperature-controlled circulating peritoneal dialysis in combination with temperature-controlled hypoxic and hypercapnic gas mixtures. The average cooling time necessary for the esophageal temperature to decrease from 37.7 degrees +/- 0.7 to 20.6 degrees +/- 1.... |
A 28-year-old woman had a ruptured solitary pulmonary arterial aneurysm which was successfully treated by pericardial patch graft. The etiology of the aneurysm could not be determined although the patient had had several episodes of blunt chest trauma in the past. Unusual aspects of this case include: location of the a... |
The beta-adrenergic blocking agent, timolol, administered to resting rabbits as an i.v. bolus (0.125 mg/kg) sustained by a 2-hr infusion at 0.0625 mg/kg/hr, caused significant depression of plasma renin activity (PRA) to 49% of the control level. Significant correlations emerged between the fall in mean blood pressure ... |
Sodium acetate (AC) is routinely used in dialysis solutions in hemodialysis units as it provides a ready source of fixed base. The renal dynamics of the buffer salt are not well known. Anesthetized dogs received i.v. infusions of AC at a rate of 40 to 600 muEq/kg/min. Urinary AC and bicarbonate excretion was measured a... |
The actions of ketamine, etoxadrol and thiopental on continuous avoidance behavior in the rat were evaluated following i.v. administration. Ketamine and thiopental exerted only a depressant effect on avoidance behavior which was attributable to the anesthetic properties of the drugs. In contrast, biphasic activity was ... |
In the last part of this series we have studied the effects of various drugs on ponto-geniculo-occipital (PGO) waves induced by the benzoquinolizine derivative, Ro 4-1284 (PGO(1284)), and by the inhibitor of trypotophan hydroxylase, p-chlorophenylalanine (PGO(PCPA)), and continuously recorder and counted in the lateral... |
Seventeen strains of nitrogen-fixing bacteria, isolated from different habitats on hydrogen and carbon dioxide as well as on other substrates, morphologically resembled each other. All strains, including Mycobacterium flavum 301, grew autotrophically with hydrogen. The isolate strain 6 was sensitive to oxygen when depe... |
An ammonia-oxidizing bacterium was isolated from a sample of brackish water (North Sea, Harbour of Husum). It is a motile large coccus 1.5-1.7 mum in diameter. The extensive cytomembrane system occurring as flattened vesicles in the peripheral region of the cytoplasm and as intrusions into the center of the cytoplasm i... |
An ammonia-oxidizing, autotroph growing, slender, curved rod was isolated from the soil of Hawaii. It is well distinguishable from any other nitrifying bacteria thus far described by their morphology. The cells are 1.1-3.0 mum long and 0.3-0.4 mum wide. They are motile by means of 1-4 subpolar to lateral flagella. In c... |
A method is described for the isolation of heterocysts that are virtually free of contaminating cell debris after sonication of aerobically grown Anabaena 7120. Isolated heterocysts reduced acetylene in a light-dependent process in the absence of exogenously provided ATP; heterocysts supplied with ATP and Na2S2O4 reduc... |
Nutritional and physical conditions affecting nitrogenase activity in the strain of "cowpea" rhizobia, 32H1, were examined using cultures grown on agar medium. Arabinose in the basic medium (CS7) could be replaced by ribose, xylose, or glycerol, but mannitol, glucose, sucrose, or galactose only supported low nitrogenas... |
Ribulose bisphosphate carboxylase (EC 4.1.1.39) from Thiobacillus A2 has been purified to homogeneity on the basis of polyacrylamide gel electrophoresis and U.V. analysis during sedimentation velocity studies. The enzyme had an optimum pH of about 8.2 with Tris-HCl buffers. The molecular weight was about 521000 with an... |
There was a high activity of alkaline phosphatase in the blood plasma of piglets during the first few days of live; enzyme obtained at this time had high heat stability and was readily inhibited by L-phenylalanine (5 mM). The enzyme in blood was inhibited to a greater extent than alkaline phosphatase from intestinal mu... |
Changes in enzymatic activities in phosphorolytic and hydrolytic glycogenolysis in the working heart and in resting skeletal muscle after intravenous injection of sympathicolytic compounds were studied in vitro. Reserpine, alderline and ligation of the adrenals inhibited the influence of acetylcholine on phosphorylase,... |
The article deals with the experience in organization of practical conferences in Moscow (The Central Institute of Advanced Medical Training) and in Lvov. The conferences enable pathoanatomists of various institutions to obtain consultation concerning bioptic material, to exchange view with regard for any individual ob... |
Static performance characteristics of current-inventory USAF oxygen regulators were evaluated with the use of a specialized regulator test stand. Outlet suction pressures, flows, positive pressures, and delivered oxygen dilutions were monitored and recorded as functions of operational altitudes. General findings indica... |
Several oxygen regulators were quantitatively assessed during interface with dynamic respiratory simulation and human user breathing. Continuous measurements of regulator flow, delivered pressure, and delivered oxygenation was provided during variable tidal volumes and breathing frequencies as accomplished initially wi... |
Acetyl-CoA synthase (EC 6.2.1.1), Propionyl-CoA synthase (EC 6.2.1.-) and butyryl-CoA synthase (EC 6.2.1.2) were measured in subcellular fractions prepared by primary and density-gradient fractionation from adult rat brain by a method resulting in recoveries close to 100%. Most of the activity of the three enzymes was ... |
Stoicheometries and rates of proton translocation associated with respiratory reduction of NO3- have been measured for spheroplasts of Escherichia coli grown anaerobically in the presence of NO3-. Observed stoicheiometries [leads to H+/NO3- ratio; P. Mitchell (1966) Chemiosmotic Coupling in Oxidative and Photosynthetic... |
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 perform... |
1. Chlorophyll (ide) formation from protochlorophyll (ide) that is normally inactive was demonstrated in etioplast membranes isolated from maize and barlley plants, the process being dependent on intermittent illumination and the addition of NADPH. 2. The addition of NADPH to the membranes was shown to result in the co... |
1. The apparent Km values for succinate uptake by whole cells of Escherichia coli K12 depend on pH in the range 6.5-7.4.2. Uptake of succinate in lightly buffered medium is accompanied by proton uptake. 3. The apparent Km values for succinate uptake and for succinate-induced proton uptake are similar. 4. Approximately ... |
The GSH concentration of rabbit erythrocytes was monitored under conditions of large net transport of alanine, phenylalane and lysine in the absence of glucose. In no case was there an appreciable alteration in GSH concentration during amino acid uptake. It is suggested that the gamma-glutamyltransferase-gamma-glutamyl... |
Cytochrome c insolubilized on to agarose gel was shown to be more resistant to denaturation and carboxymethylation than the soluble protein. These differences are discussed both with respect to the conformational changes that take place during denaturation of cytochrome c and with respect to the pH-dependent forms of c... |
The citrate synthase activity of Acetobacter xylinum cells grown on glucose was the same as of cells grown on intermediates of the tricarboxylic acid cycle. The activity of citrate synthase in extracts is compatible with the overall rate of acetate oxidation in vivo. The enzyme was purified 47-fold from sonic extracts ... |
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-ch... |
1. The hydrolytic and transfer reactions catalysed by rat kidney-gamma-glutamyltransferase (EC 2.3.2.2) were studied in vitro with substrates [U-14C]glutamic acid-labelled glutathione and methionine. Initial-velocity patterns, isotope-exchange and binding studies were consistent with a branched non-sequential mechanism... |
An investigation of the behavior of protoporphyrin IX, deuteroporphyrin IX, haematoporphyrin IX and coproporphyrin III in aqueous solution revealed extensive and complex aggregation processes. Protoporphyrin appears to be highly aggregated under all conditions studied. At concentrations below 4 muM, aggregation of deut... |
The kinetic properties of a maltase-glucoamylase complex with a neutral pH optimum, purified to homogeneity from the brush borders of the rabbit small intestine, are described. It has a broad range of substrate specificity, hydrolysing di- and poly-saccharides with alpha-1,4 and alpha-1,6 linkages. The Km and Vmax, val... |
1. Analysis of bile salts of four snakes of the subfamily Viperinae showed that their bile acids consisted mainly of C-23-hydroxylated bile acids. 2. Incubations of 14C-labelled sodium cholate (3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholan-24-oate) and deoxycholate (3 alpha, 12 alpha-dihydroxy-5 beta-cholan-24-oa... |
Cytoplasmic granules were isolated from horse blood polymorphonuclear leucocytes by the heparin method and extracted with 0.9% NaCl by repeated freezing. Soluble proteins were separated on a column of Sephadex G-75 followed by chromatography on a column of CM-Sephadex with a NaCl gradient. Gel filtration, density-gradi... |
Two proteinases (2A and 2B) purified from the granular fraction of horse blood leucocytes degrade casein (Km values 12.8 and 6mg/ml respectively) with maximum activity at pH 7.4 and in the presence of 2m-urea. Urea-denatured haemoglobin, fibrinogen, albumin and resorcin/fuchsin-stained elastin are digested at a slower ... |
1. A purification scheme for an arylsulphatase B from human liver is described. Specificity of purification was achieved by the use of the affinity chromatography on an agrose-4-hydroxy-2-nitrophenyl sulphate derivative. The scheme provides a rapid and convenient method for preparation of a highly purified enzyme. 2. T... |
If the Michaelis constant of an enzyme-catalysed reaction is independent of pH under conditions where the catalytic constant varies with pH, it is equal to the thermodynamic dissociation constant of the enzyme-substrate complex. This is true for realistic mechanisms in which binding and catalytic steps, are clearly dis... |
1. Acetyl-Coa carboxylase from lactating-rabbit mammary gland was purified to homogeneity by the criterion of polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. 2. Use of phosphate buffer throughout the purification gave low recovery of enzyme. Consequently, Tris buffers were used in the ext... |
When polystyrene "latex" beads are centrifuged to equilibrium in gradients of Nalcoag 1030, Nalcoag 1034A and Ludox 130M, which are commercial formulations of colloidal silica, the beads at densities that may be markedly lower or higher than the bulk density. Addition to the gradient of small amounts of certain polymer... |
In the oxidation of methylglyoxal by 2-oxoaldehyde dehydrogenase, the apparent Km value for NADP+ was about 2.5 times lower than the corresponding Km for NAD+; the apparent Km values for methylglyoxal and for the amine activator L-2-aminopropan-1-ol, with NADP+ as cofactor, were also different from those obtained with ... |
Lipid synthesis as measured by the incorporation of acetate or 3H2O into slices of foetal liver, is much higher than in slices of adult liver and shows a peak at about two-thirds of gestation. At this time the synthesis from glucose was low and reached a peak 10 days later. The changes in the activity of ATP citrate ly... |
1. Exposure of slices of cerebral cortex from guinea pigs to electrical pulses for 10s or to noradrenaline, 5-hydroxytryptamine or histamine increases the rate of phosphorylation of unidentified proteins in the tissue; the increases in protein phosphorylation due to electrical pulses and noradrenaline were non-additive... |
ADP was shown to inhibit phosphoglycerate-dependent O2 evolution in a simplified reconstituted chloroplast system containing 3-phosphoglycerate kinase and triose phosphate dehydrogenase. Rates of O2 evolution in the simplified system are comparable with those obtained by using stromal protein rather than purified enzym... |
1. Pyruvate dehydrogenase phosphate phosphatase activity in rat epididymal fat-pads was measured by using pig heart pyruvate dehydrogenase [32P]phosphate. About 80% was found to be extramitochondrial and therefore probably not directly concerned with the regulation of pyruvate dehydrogenase activity. The extramitochond... |
Tyrosine aminotransferase is present at low activity in the rabbit placenta. The activity can be enhanced by injecting the pregnant mother with insulin or cortisol. This response decreases over the last half of gestation (14-28 days gestational age). |
1. Changes in the activities of several enzymes involved in mitochondrial fatty acid oxidation were measured in livers of developing rats between late foetal life and maturity. The enzymes studied are medium- and long-chain ATP-dependent acyl-CoA synthetases of the outer mitochondrial membrane and matrix, GTP-dependent... |
A sex difference in postanaesthetic mortality after fluroxene anaesthesia was found in Swiss Webster mice. More males succumbed than females. This toxicity was biotransformation-dependent and could be reversed by pretreatment with "opposite" sex hormones. The toxicity of the fluroxene metabolite trifluoroethanol also w... |
Illumination of envelope vesicles prepared from Halobacterium halobium cells causes translocation of protons from inside to outside, due to the light-induced cycling of bacteriorhodopsin. This process results in a pH gradient across the membranes, an electrical potential, and the movements of K+ and Na+. The electrical... |
A novel phosphodiesterase was purified from cultured tobacco cells to a state which appeared homogeneous on polyacrylamide gel electrophoresis. The enzyme hydrolyzed various phosphodiester and pyrophosphate bonds, including p-nitrophenyl thymidine 5'-phosphate, p-nitrophenyl thymidine 3'-phosphate, cyclic nucleotides, ... |
Carbonyl complexes of horse cytochrome c and various carboxymethylated derivatives have been examined using 13C NMR (carbon-13 nuclear magnetic resonance) spectroscopy. The multiplicity and chemical shift of the 13CO resonance were found to be functions of pH and the extent of alkylation. Correlations have been made am... |
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 t... |
The pH dependence of the proton NMR spectrum of [Asn1, Val5] angiotensin II in aqueous solution shows the existence of one major and one minor conformation above pH 6.5, the minor conformation representing 12 +/- 2% of the total peptide. A similar observation has been made for (Asn1, Val5) angiotensin I and Val-Tyr-Val... |
The stereochemistry of the intramolecular proton transfer catalyzed by the flavoenzyme, D-amino-acid oxidase, during the elimination reaction of beta-chloro-alpha-amino acid substrates (Walsh et al. (1973), J. Biol. Chem. 248, 1964) has been established. Both D-erythro- and D-threo-2-amino-3-chloro(2-3H) butyrate have ... |
The multiple cholinesterase activities in canine platelets have been investigated. Platelets were homogenized by rapid decompression under nitrogen, glass tube/Teflon pestle, and glycerol lysis techniques. Rapid decompression under nitrogen technique was found to be the most efficient and gentle method for cell disrupt... |
The effect of Ca2+ in vitro on pregnenolone production rates under various incubation conditions by mitochondrial fractions isolated from testes of normal rats and of rats after in vivo treatment with luteinizing hormone has been investigated. Concentrations of Ca2+ in the range of 0.1-0.5 mM stimulated succinate suppo... |
The subcellular localizations of guanylate cyclase and 3',5'-cyclic nucleotide phosphodiesterase in sea urchin sperm were examined. Both the specific and total activities of these two enzymes were much higher in sperm flagella (tails) than in the heads. In addition to the observation that guanylate cyclase in the flage... |
Auxotrophic mutants of Escherichia coli W or K12 blocked before shikimic acid in the aromatic biosynthetic pathway grew poorly on shikimic acid as sole aromatic supplement. This poor growth response was correlated with a relatively poor ability to transport shikimic acid. If citrate was present in the growth medium (as... |
A cell-free particulate enzyme preparation of Mycobacterium smegmatis ATCC 607 catalyzed the transfer of labeled mannose from GDP[14C] mannose to methyl-alpha-D-mannopyranoside (an exogenously added acceptor) to form a product that was characterized to be 2-O-alpha-D[14C] mannopyranosyl-methyl-alpha-D-mannopyranoside. ... |
1. A microsomal enzyme preparation from the yeast Saccharomyces cerevisiae catalyzes the transfer of mannosyl units from GDPmannose to mannose and a number of mannose-containing oligosaccharides and glycosides whereby different glycosidic bonds are formed. 2. Of the compounds tested besides mannose, only those containi... |
The effect of riboflavin and iron on 6-hydroxy-2,4,5-triaminopyrimidine synthesis rate was investigated in the cultures of the yeast Pichia guilliermondii (rib2 mutants) with the blocked second reaction to flavinogenesis. It was shown that riboflavin inhibited the 6-hydroxy-2,4,5-triaminopyrimidine synthesis rate in ir... |
Pediococcus cerevisiae/AMr, resistant to amethopterin, possesses a higher dihydrofolate reductase (5, 6, 7, 8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) activity than the parent, a folate-permeable and thus amethopterin-susceptible strain and than the wild-type. The properties of dihydrofolate reductase from t... |
the accumulation of amethopterin in a Pediococcus cerevisiae strain resistant to this analogue was about 30% of that in P. cerevisiae/PteGlu, the sensitive parent. The uptake in the resistant strain was strictly glucose dependent, whereas in the sensitive parent about 16% accumulation occurred in absence of glucose. Th... |
The apparent pK for benzimidazole displacement of a number of cobalamins is markedly affected by the presence of sodium lauryl sulfate micelles. However, micelles of cetyltrimethylammonium bromide or Triton X have little or no effect on the pK. By measuring the apparent pK as a function of sodium lauryl sulfate concent... |
Human diferric transferrin was partially labeled with 59Fe at low or neutral pH (chemically labeled) and by replacement of diferric iron previously donated to rabbit reticulocytes (biologically labeled). Reticulocyte 59Fe uptake experiments with chemically labeled preparations indicated that iron bound at near neutral ... |
The pH dependence of the spectra and of the oxidation-reduction potential of three cytochromes c2, from Rhodopseudomonas capsulata, Rhodopseudomonas sphaeroides and Rhodomicrobium vannielii, were studied. A single alkaline pK was observed for the spectral changes in all three ferricytochromes. In Rps. capsulata cytochr... |
The iron-sulfur proteins of the green photosynthetic bacterium Chlorobium have been characterized by oxidation-reduction potentiometry in conjunction with low-temperature electron paramagnetic resonance spectroscopy. Chlorobium ferredoxin was the only iron-sulfur protein detected in the soluble fraction; no high-potent... |
(1) Tb3+ binding to mitochondrial membranes can be monitored by enhanced ion fluorescence at 545 nm with excitation at 285 nm. At low protein concentrations (less than 30 mug/ml) no inner filter effects are observed. (2) This binding is localized at the external surface of the inner membrane and is unaffected by inhibi... |
The inhibitory effect of tRNA on yeast 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP) synthase (EC 4.1.2.15) has been reinvestigated. From earlier studies the inhibition by tRNAPhe appeared to be quite specific. This study shows that tRNAPhe is indeed a potent inhibitor but so is unfractionated tRNA, as well as rib... |
Aspects of a possible involvement of hydrogen ions in the electrophysiological responses to light of Limulus ventral photoreceptors were investigated. A 1 M solution of either a zwitter-ionic pH buffer or a weakly-buffering control substance was pressure injected through a micropipette into a ventral photoreceptor cell... |
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 ... |
Plasma membrane from fusing embryonic muscle cells were assayed for phospholipase A activity to determine if this enzyme plays a role in cell fusion. The membranes were assayed under a variety of conditions with phosphatidylcholine as the substrate and no phospholipase A activity was found. The plasma membranes did con... |
Two membrane fractions prepared from the Ehrlich ascites-tumor cell show non-identical stimulatory responses to certain amino acids in their Mg+2 -dependent activity to cleave ATP, despite the presence of ouabain and the absence of Na+ or K+. The first of these, previously described, shows little (Na+ + K+)-ATPase acti... |
Gamma-glutamyl transpeptidase was purified 53 times from Sheep brain cortex capillaries. On gel filtration it appears homogeneous with a M.W. = 350 000. The enzyme is likely a glycoprotein, the properties of which are close to hog kidney gamma-glutamyl transpeptidase ; gamma-glutamyl aminoacid formation is assayed elec... |
Incorporation of malonyl-CoA or acetyl-CoA is studied in mouse brain mitochondrial fatty acids. Rupture of mitochondria is necessary ; Triton X-100 gives the best result. Other detergents or sonication are of lesser efficiency. Cofactor requirements have been studied : NADH and NADPH have been tested ; ATP increases bi... |
The dependency of L-asparagine hydrolysis rate on L-asparagine concentration in the presence of L-asparaginases from E. coli and Erw. carotovora is studied in a broad pH range. Km values are calculated from the data obtained. It is found that Km insignificantly depends on pH value with the pH range of 5-9 for both aspa... |
The endogenous RNApolymerase activity of isolated cell nuclei and chloroplasts from young pea plants (Pisum sativum) has been studied. The presence of all four nucleoside triphosphates and Mg2+ ions is necessary for the reaction. The missing of one of these nucleotides from the reaction mixture, especially ATP, sharply... |
Effect of different products of glutamine metabolism on the activity of glutamine synthetase in the presence of Mg2+, and Mn2+ and Co2+ as cofactors is studied. All the metabolites studied are found to inhibit the glutamine synthetase activity in the presence of any cation listed. The degree and the character of the in... |
Carboanhydrase (carbonate-hydroliase EC 4.2.1.1.) is found in the extract of Spirulina platensis cells. A linear dependency of the enzyme activity on the protein concentration; pH optimum is found to be 8.0. Specific activity of carboanhydrase is 3 muM/min-mg of protein under the concentration of CO2 of 4-10(-3) M, app... |
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-cel... |
Ring dichroism spectra (RD) of histidine decarboxylase (HDC) from Micrococcus sp. n. at the regions of peptide bonds (200-240 nm) and aromatic amino acids (250-300 nm) absorption are studied. The treatment of RD spectra according to methods of Greenfield-Fasman, Saksena-Vetlaufer and Mayer permits to conclude that at t... |
Enzymatic and physico-chemical properties of homogenous preparation of carboxypeptidase from Streptomyces griseus are studied. pH-Optimum is found to be 7.9 and 8.2 under the hydrolysis of cbs-Gly-Leu and hyppuryl-arg respectively, temperature optimum --60 degrees C. The enzyme splits more efficiently basic amino acids... |
The sub-cellular topography of oxidative and non-oxidative enzymes of the pentose phosphate pathway of carbohydrates metabolism and enzymes of the nucleic exchange (acid and alkaline deoxyribonucleases and ribonucleases) in chicken liver is studied. Nuclear and mitochondrial forms of the enzymes are discovered. The act... |
Riboflavin kinase (E.C.2.7.1.26) was isolated from the cells of the yeast Pichia guilliermondii. The enzyme was 680-fold purified uzing ammonium sulphate fractionation, chromatography on DEAE-Sephadex A-50 and CM-Sephadex C-50 and gel-filtration through Sephadex G-75. Purified enzyme preparation was free from phosphata... |
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. Th... |
Conditions of phospholipase D adsorption on silica gels have been studied. The immobilized phospholipase D is shown to differ from the soluble form in thermostability, pH optima and activation conditions. A question is discussed as to the connection of the use of activators and the adsorption immobilization. It is assu... |
Resting bone marrow lymphocytes, recongised as small lymphocytes by light microscopy, were labelled by the complete 3H-thymidine labelling technique, enriched by fractionation on a discontinuous albumin gradient and investigated for their stem cell properties by culture in diffusion chambers. Fraction 3, with the highe... |
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 bo... |
Different amount of intact or irradiated bone marrow from syngenous donors was administered to mice irradiated with a lethal dose. There was revealed a linear dependence of the number of the 8-9-day colonies grown in the bone marrow of the femur on the amount of the administered cells, and an exponential dependence on ... |
Experiments were conducted on rats; a study was made of methionineS35 incorporation into the sum total proteins isolated from various portions of the brain after a single administration of chlorpromazine, majeptil and tricedil. A generalized depression of protein synthesis in all the structures, except the medulla oblo... |
Experiments were performed on the smooth muscle cells of rabbit a. pulmonalis using the microelectrode technique. No spontaneous electrical or mechanical activity was recorded in normal Krebs solution. The current-voltage relation in these smooth muscle cells showed marked rectification. No changes in the isometric ten... |
Ethylenediamine tetraacetate and mechanical treatment were applied to obtain the isolated hepatocytes. Oxidative phosphorylation was found to be preserved in the isolated cells. Hepatocytes were capable of hydroxylation of dimethylaniline (DMA), ethylmorphine and aminopyrine. VMAX for the hydroxylation of DMA calculate... |
The influence of carbidine, an original psychotropic drug, on the adrenergic neurotransmitter content and storage in the sympathetic nerves was studied with the use of cytochemical electron microscopy. The influence of carbidine on the uptake of the exogenous noradrenaline (NA) in the synaptic vesicles was also studied... |
Isoenzymes NAD-and NaDP MDH were detected in the cardiac muscle of rabbits by disc electrophoresis in polyacrylamide gel. Alloxan diabetes proved to be accompanied by a significant reduction in the activity of mitochondrial NADP MDH (in the reaction of malic decarboxylation) and its increase in cytozol. The activity of... |
A study was made of the influence of ciproheptadin, serotonin and histamine inhibitor, on the effects of exo- and endogenous bradykinin. Ciproheptadin inhibited the effect of bradykinin on a section of a guinea pig intestine in vitro, eliminated the hypotensive effect of bradykinin in rats in vivo, and also blocked the... |
Adenosine triphosphatase (ATPase) activated by Mg2+ or Ca2+ ions was detected in single mechanoreceptors (Pacini's corpuscles) of cat; addition of Ca2+ (10(-5)M) to Mg-ATP-ase increased the activity by the factor of 1.6. The activity optimum of Mg- or Co-ATPase was in the alkaline pH zone. A high substrate specificity ... |
The activity of cytoplasmic dehydrogenases of the adrenal cells was examined during the prolonged injections of ACTH to Wistar rats. The indices of specific steroid synthesis function of the glands remained relatively high in the course of the whole experiment. Changes in the rats of corticosterone synthesis and dehydr... |
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