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The mechanisms of the low availability of endogenous folates in orange juice and the inhibitory effects on the availability of pteroylheptaglutamate (PteGlu7) caused by orange juice supplements were investigated in man by the use of simulated orange juice (containing the principal components: citric acid, malic acid, e... |
The measurement of pH, PO2, PCO2 and SO2 in a single venous blood sample can be used to determine the P50 at standard or at in vivo conditions. This technique makes it feasible for a physician, firstly, to make an assessment of the net adaptation of the red cell to reductions in blood oxygen content or flow and, second... |
The bacterial protein colicin K, when added to sensitive Escherichia coli in the presence of 3,3'-dihexyloxacarbocyanine, cuases a doubling in fluorescence of the probe. Glucose and oxygen cause a decreased fluorescence while anoxia and cyanide cause a rise in fluorescence. These results in conjunction with the work of... |
Phenacylcobalamin has been synthesized and characterized by thin-layer chromatography and uv-visible spectroscopy, as well as identification of the cobalt-containing and organic products of its cleavage in acid and base and by aerobic photolysis. The major organic product from all three cleavage reactions is acetopheno... |
New experimental data and a quantitative theoretical treatment are given for the kinetics of the thermal folding transition of ribonuclease A at pH 3.0. A three-species mechanism is used as a starting point for the analysis: U1 (slow) in equilibrium U2(fast) in equilibrium N, where U1 and U2 are two forms of the unfold... |
The relative rate of the hydrolysis of 2-(5-n-alkyl)furoyl-alpha-chymotrypsin reaches a maximum with the propyl derivative. The Arrhenius plots for the hydrolyses of the 2-furoyl-, 2-(5-ethyl)furoyl-, and 2-(5-n-propyl)furoyl-alpha-chymotrypsins display a discontinuity, while the plots obtained with the ramaining furoy... |
A subclass of nonhistone chromatin proteins with high DNA affinity has been isolated from rat liver. The interaction of the isolated proteins with DNA in vitro was characterized utilizing a nitrocellulose filter binding technique. The temperature, time, concentration, ionic strength, and pH dependence were characterize... |
Membrane vesicles can be prepared from murine lymphoid cells by nitrogen cavitation and fractionated by sedimentation through nonlinear sucrose density gradients. Two subpopulations of membrane vesicles, PMI and PMII, can be distinguished on the basis of sedimentation rate. The subcellular distribution of adenylate and... |
19F nuclear magnetic resonance (NMR) spectroscopy has been used to study a fully active E. coli fluorotyrosine alkaline phosphatase. The fluorotyrosine resonances provide sensitive probes of the conformational states of the protein. They were used to follow the addition of zinc or cobalt to the apoprotein, and the titr... |
31P nuclear magnetic resonance (NMR) was used to directly observe the binding of inorganic phosphate to alkaline phosphatase. Evidencq for the tight binding of 1.5-2.0 mol of inorganic phosphate per dimer of alkaline phosphatase is presented. Two distinct forms of bound phosphate are observed, one predominating above p... |
The autophosphorylation of rabbit and human erythrocyte membranes has been studied under various experimental conditions. The phosphopeptides of the erythocyte membranes were identified using sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis followed by ratioautography. The pattern of phosphorylatiion of m... |
The glutamine synthetase adenylyltransferase (EC 2.7.7.42), WHIch catalyzes the adenylylation and deadenylylation of glutamine synthetase in E. coli, has been stabilized and purified 2200-fold to apparent homogeneity. Sedimentation and electrophoresis studies show that the native enzyme is a single polypeptide chain of... |
The incubation of 1-[3H)dolichols with cell-free preparations from various rat tissues resulted in the formation of a labeled material which possessed the characteristics of synthetic dolichol palmitate. Rat liver microsomes were found to be a good source of the acyltransferase activity, and the properties of the react... |
The myeloma IgA protein produced by plasmacytoma XRPC-25, was isolated by affinity chromatography on dinitrophenyllysine-Sepharose. The affinity constant of the intact protein or its Fab' toward 2,4-dinitrophenyl-L-lysine (Dnp) was found to be 2.6 X 10(5) M-1. In order to prepare an Fv fragment (Hochman, J., Inbar, D.,... |
1. A soluble protein with a molecular weight of 11-12-10(3) has been isolated from bovine-heart mitochondria, which stimulates the following ATP-dependent reactions of submitochondrial particles treated with 0.6 mM EDTA and 1 M NH4OH: reverse electron transfer from succinate to NAD, transhydrogenation from NADH to NADP... |
The intermediate phase of fluorescence relaxation (lms-ls) (Joliot, P., Joliot, A., Bouges, B, and Barbieri, G. (1971) Photochem. Photobiol. 14, 287-305), following a single saturating flash, is shown to be controlled by a slow phase of the reoxidation of Q- by a secondary acceptor and, in vivo, by the transmembrane el... |
Using a rapid pH electrode, measurements were made of the flash-induced proton transport in isolated spinach chloroplasts. To calibrate the system, we assumed that in the presence of ferricyanide and in steady-state flashing light, each flash liberates from water one proton per reaction chain. We concluded that with bo... |
During the "respiratory adaptation" of Bacillus coagulans, it was possible to dissociate the kinetics of cytochrome a and a3 synthesis with carbon monoxide. The synthesis of cytochrome a3 is preferentially repressed when the pH of the incubation medium is pH 6.5 instead of pH 5.5. However, though the total synthesis of... |
Both phospholipases A1 and A2 activities (EC 3.1.1.4) at pH 7.4 were found to be significantly decreased in retinol-deficient rat testes supplemented with retinoic acid as compared to retinol-fed controls using 1-acyl-2-[1-(14)C]-oleoyl-sn-glycero-3-phosphocholine as substrate. However, little or no difference was obse... |
1. The cloacin DF13-induced inactivation of ribosomes in vitro can be described as an enzyme-catalyzed reaction according to the Michaelis-Menten equation. Most probably the cloacin acts as a unique endoribonuclease. 2. At pH 7.8 and 37 degrees C the Km value for the reaction of cloacin DF13 with ribosomes is 13.2 - 10... |
The tRNA methyltransferases from Paramecium aurelia were investigated. The effects of varying the Mg2+ and NH4+ concentrations, pH, and temperature on the methylation of Escherichia coli B tRNA using extracts from P. aurelia were determined. Optimum tRNA methyltransferase activity was observed at pH 7.8 and 37 degrees ... |
1. The effect of pH on the buoyant density of the complexes of Ag+ with DNA has been studied using 3H-labeled human DNA and several bacterial DNAs to determine the conditions necessary for the maximum resolution of compositional heterogeneity. In neutral CS2SO4 density gradients, Ag+ complexes with (G - C)-rich compone... |
Direct comparison of purple membrane preparations from Halobacterium cutirubrum and Halobacterium halobium was carried out. Both preparations were found to be essentially identical with respect to their molecular weight, retinal content, lipid composition, fingerprinting of peptides from peptide digestion, electron mic... |
(1) The effect of surface charge upon the kinetics of monovalent cation translocation via a two-site mechanism is investigated theroretically. (2) According to the model dealt with, typical relations are expected for the dependence of the kinetic parameters of the translocation process upon the concentration of a polyv... |
The sweet protein monellin [1-3] has been shown to consist of two non-identical subunits of 50 and 42 amino acid residues, which were separated electrophoretically and chromatographically. Automatic sequential Edman degradation gave the complete sequence of the longer subunit, and a partial sequency of the shorter one.... |
The 3-phosphoglycerate kinase (EC 2.7.2.3) of yeast which contains two tryptophyl and eight tyrosyl residues per molecule, displayed an unusualy fluorescence emission spectrum with a maximum at 308 nm when excited at 280 nm. The emission peak shifted to 329 nm when excited at 295 nm. We could confirm that it was due to... |
Binding of [14, 15-3H](+/-)-norgestrel to human plasma proteins has been investigated. Norgestrel showed greater affinity to plasma than to human serum albumin indicating specific norgestrel binding protein(s) in the plasma. alpha1-acid glycoprotein showed high affinity for norgestrel when compared with human serum alb... |
The reversible unfolding of alpha-lactalbumin by guanidine hydrochloride, was studied at 25.0 degrees C in a relatively low concentration range of the denaturant (0.80-2.00 mol/l) by means of difference spectra and pH-jump measurements. The unfolding was shown to occur between two states, N and D, because apparent rate... |
Studies of the iodide ion quenching of the intrinsic fluorescence of Concanavalin A indicate that 50% of the tryptophyl fluorescence originates from exposed residues. This agrees with the X-ray crystallographic determination that two of the four tryptophan residues in a Concanavalin A monomer are on the surface. Previo... |
A comparison of the conformation of Folch-Pi apoprotein in organic solvent and in aqueous solutions has been made by ESR, infrared and circular dichroism spectroscopy studies. Electrophoresis and ultracentrifugation have been carried out in order to correlate molecular weight and charge of the molecule with its conform... |
The time course of the rate of the glycolysis of human erythrocytes and of some metabolites were determined before and after rapid deoxygenation at constant intracellular pH. For this purpose stripped deoxygenated haemoglobin was used as a rapid oxygen acceptor. Deoxygenation causes an increase of the glycolytic rate b... |
A weak base, morpholine, has been labelled with 3H and tested for its suitability as an indicator for intracellular pH, by distribution in the tissue water of frog sartorius muscle in the species Hyla litoria. Its pK'a at 20 degrees C in a solution of the same ionic strength as frog Ringer was found to be 8.45 +/- 0.02... |
Cyclic guanosine 3',5'-monophosphate (cyclic GMP) stimulates nucleic acid synthesis in lymphocytes, and has been implicated as the intracellular effector of the actions of mitogenic agents on these cells. In the present study, we examined the specificity of the mitogenic activity of cyclic GMP and of its 8-bromo (Br) d... |
1. Four fractions of protein kinase (EC 2.7.1.37) activity (Peak IH, IIH, IIIC and IVC) have been resolved and partially purified from the 100 000 X g supernatant fraction of bovine parotid glands by DEAE-cellulose and phosphocellulose chromatographies. 2. The protein kinases of Peak IH and IIH were adenosine 3',5'-mon... |
The enzyme rhodanese (EC 2.8.1.1) appears as a single polypeptide chain protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight of this species is approx. 33 000. This contrasts with previous reports that rhodanese behaves on gel filtration chromatography as a rapidly equilibrating mo... |
Esterase A (EC 3.1.1.1) obtained by sonic disruption of Bacillus subtilis SR22 (spoA12, trpC2) was purified approximately 400-fold by differential chemical and heating precipitation, DEAE-cellulose chromatography, and Bio-Rad P-150 gel filtration chromatography, with an overall yield of 59%. The purified enzyme hydroly... |
Alkaline phosphatase (EC 3.1.3.1) from cow's milk as a dimer comprising two identical or very similar subunits of about 85 000 molecular weight. The enzyme contains 4.9 +/- 0.6 gatoms of zinc per mol of protein. The essential kinetic properties are the same as those of other alkaline phosphatases: variation of pH optim... |
Some of the kinetic properties of angiotensin-converting enzyme (peptidyl-dipeptide hydrolase, EC 3.4.15.1) purified from hog lung have been determined using hippurylglycylglycine as substrate. The effects of pH and ionic environment on enzyme activity are complex and interdependent. At 0.1 M NaCl, the pH-activity curv... |
Euglena gracilis z contained two succinic semialdehyde dehydrogenases (EC 1.2.1.16), one requiring NAD and the other NADP, and these isozymes were separated from each other and partially purified. The NAD-linked isozyme was relatively stable on storage at 5 degrees C whereas the NADP-linked one was extremely unstable u... |
The activity of a partially purified preparation of tyrosine hydroxylase (EC 1.14.16.2) from the bovine caudate nucleus was increased by heparin, chondroitin sulfate, phosphatidylserine, polyacrylic acid, polyvinyl sulfuric acid and both poly-D-, and poly-L-glutamic acids, all polyanions. A variety of salts both activa... |
The properties of enzymes catalysing the transfer of a galactose from UDP-galactose to exogenous ceramide monohexoside and ceramide di-hexoside derived from the Syrian hamster cell line NIL 2 were studied. The products of these enzymes were characterized by chemical and enzymatic methods. Kinetic analyses showed that t... |
(1) The pH dependence of the kinetic parameters of the reaction catalyzed by pigeon liver diacetyl reductase (EC 1.1.1.5) was investigated in the pH range 5.1-8.6. (2) From the results obtained it is postulated that: (a), a group of pK around 7, active in the protonated form, participates in the interaction of the enzy... |
Pig heart NAD-specific isocitrate dehydrogenase is inactivated by reaction with iodoacetate at pH 6.0. Loss of activity can be attributed to the formation of 1-2 mol of carboxymethyl-cysteine per peptide chain. The rate of inactivation is markedly decreased by the combined addition of Mn2+ and isocitrate, but not by al... |
1. NADP-dependent glutamate dehydrogenase (EC 1.4.1.4) extracted from nuclear fractions of Saccharomyces cerevisiae was partially purified. The final purification achieved was over 100-fold over the initial extract. 2. Cellulose acetate electrophoresis shows that the preparation is close to homogeneity and that the enz... |
The kinetics of rat liver L-type pyruvate kinase (EC 2.7.1.40), phosphorylated with cyclic AMP-stimulated protein kinase from the same source, and the unphosphorylated enzyme have been compared. The effects of pH and various concentrations of substrates, Mg2+, K+ and modifiers were studied. In the absence of fructose 1... |
The effect of denaturants on the quantitation of free sulfhydryl groups in the enzyme rhodanese (thiosulfate sulfurtransferase, EC 2.8.1.1) has been reinvestigated in some detail. The sulfhydryl assay with the colorimetric reagent 5, 5'-dithio-bis (2-nitrobenzoic acid) Nbs2 shows four sulfhydryl groups per enzyme molec... |
A steroid sulphotransferase (EC 2.8.2.2) was partially purified from female rat liver. The enzyme was active towards the substrates, dehydroepiandrosterone, epiandrosterone and pregnenolone but was inactive towards oestrogens, cholesterol and ergocalciferol. A pH optimum of 5.0 was recorded but the enzyme was unstable ... |
1. In a previous ESR study of a membrane acetylcholinesterase (EC 3.1.1.7) we found, contrary to observations by other authors, spectra indicating that the active serine might be located in a pocket of the enzyme surface. In order to inquire into this possibility, ESR spectra were studied under the influence of differe... |
The presence of alkaline phosphatase (EC 3.1.3.1) activity has been demonstrated in nuclei of rat ventral prostate. This enzyme activity remained after washing of isolated nuclei with 0.5% Triton X-100; an acid phosphatase initially present with the nuclear fraction was removed by this treatment. The nuclear alkaline p... |
Potato acid phosphatase (EC 3.1.3.2) was used to remove the eight phosphate groups from alphas1-casein. Unlike most acid phosphatases, which are active at pH 6.0 or below, potato acid phosphatase can catalyze the dephosphorylation of alphas1-casein at pH 7.0. Although phosphate inhibition is considerable (K1=0.42 mM ph... |
Pig epidermal cyclic nucleotide phosphodiesterases (EC 3.1.4.16) have been partially purified by DEAE-cellulose column chromatography. At least three different forms of the epidermal phosphodiesterases were identified. They were cyclic GMP-specific, cyclic GMP- and cyclic AMP-hydrolyzing and apparently a cyclic AMP-spe... |
Pure human arylsulfatase A (EC 3.1.6.1) was found to hydrolyze ascorbic acid 2-sulfate to ascorbic acid and inorganic sulfate at rates from 200 to 2000 mumol/mg per h depending on the method of assay. This rate was lower than that observed with the synthetic substrate 4-nitrocatechol sulfate, but higher than that seen ... |
Four major forms of alpha-fucosidase (EC 3.2.1.51) activity were separated by isoelectrofocusing from sera of normal control individuals. All forms shifted towards less acidic pI values after neuraminidase treatment. In two patients affected with fucosidosis, only a single major acidic peak was observed and this was af... |
Two PZ-peptidases (EC 3.4.-) (A and B) cleaving a synthetic substrate for collagenase, 4-phenylazobenzyloxycarbonyl-L-Pro-L-Leu-Gly-L-Pro-D-Arg (PZ-peptide) have been separated from the particulate fraction of bovine dental follicle. PZ-peptidase A had a molecular weight of 220 000, an optimum pH at 8.0-8.5, and a Km v... |
The larvae of the webbing clothes moth, Tineola bisselliella contain two carboxypeptidases (EC 3.4.12-) and one of these has been purified by preparative polyacrylamide gel electrophoresis. Its pH optimum for the hydrolysis of N-benzyloxycarbonyl-glycyl-leucine was pH 7.5-7.7 and its molecular weight as judged by gel f... |
Cathepsins B1 (EC 3.4.22.1) were isolated from fetal membranes of human placenta, i.e. amnion and chorion-decidua. Purification of the enzymes was achieved by the freezing-thawing technique, ammonium sulphate fractionation and Sephadex gel filtration. Cathepsis B1 separated either from amnion or from chorion-decidua ex... |
Two forms of adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4), differing in molecular size, have been purified and obtained in homogeneous form from rabbit intestine. The purification procedures involved extraction with acetate buffer, pH 5.5, precipitation and fractional reextraction with (NH4)2SO4, ion-exch... |
(1) The proportion of higher plant chloroplast cytochrome b-559 oxidizable during illumination by low intensity 732 nm light increases as the pH is decreased below 6.5. At pH 5.0-5.3 total oxidation is seen and subsequent red light can cause reduction of up to 2/3 of the oxidized cytochrome. The oxidation by far red li... |
1. Formate inhibits cytochrome c oxidase activity both in intact mitochondria and submitochondrial particles, and in isolated cytochrome aa3. The inhibition increases with decreasing pH, indicating that HCOOH may be the inhibitory species. 2. Formate induces a blue shift in the absorption spectrum of oxidized cytochrom... |
The rate of ATP synthesis of illuminated chloroplasts is correlated with the electric conductance of their inner membranes. In agreement with previous studies it is shown that ATP synthesis is paralleled by an increased conductance of the thylakoid membrane. This conductance together with the ability to form ATP is abo... |
In strong illumination, 3-(3, 4-dichlorophenyl)-1,1-dimethylurea (DCMU)-poisoned chloroplasts exhibit a high yield of chlorophyll fluorescence while P-700 turnover, proton uptake, and phosphorylation are inhibited and a pH gradient is undectectable. When 10muM N-methylphenazonium methosulfate (PMS) is included, the flu... |
The action of xanthine oxidase upon acetaldehyde or xanthine at pH 10.2 has been shown to be accompanied by substantial accumulation of O2- during the first few minutes of the reaction. H2O2 decreases this accumulation of O2- presumably because of the Haber-Weiss reaction (H2O2+O2- leads to OH- +OH+O2) and very small a... |
The kinetics (region of seconds) of the light-induced 520 nm absorbance changes and its dark reversal have been studied in detail in the wild type and in some pigment and photosynthetic mutants of Scenedesmus obliquus. The following 5 lines of evidence led us to conclude that the signal is entirely due to the photosyst... |
The kinetics of pyruvate transport across the isolated red blood cell membrane were studied by a simple and precise spectrophotometric method: following the oxidation of NADH via lactate dehydrogenase trapped within resealed ghosts. The initial rate of pyruvate entry was linear. Influx was limited by saturation at high... |
A well-behaved water soluble iron-porphyrin system, meso-tetra-(4-carboxyphenyl) porphinato iron (III) was synthesized. Its solution behavior is described using visable and electron paramagnetic resonance (EPR) spectroscopy. The complex exists in solution as three distinct forms of bridged dimers, oxo, hydroxo and aquo... |
Sheep ovarian 17 beta HSDH has been purified about 1000 fold to a specific activity of 0.5 IU/mg protein, using DEAE cellulose chromatography, affinity chromatography on estrone-amino caproate-Sepharose and a second DEAE cellulose chromatography. The molecular weight is 70,000 ; the pH optimum for activity is 9.2 and t... |
Two forms of baker's yease valyl-tRNA synthetase have been purified to apparent homogeneity by classical methods. It was demonstrated that one of the two forms of the enzyme originates from the other by proteolysis, the respective amounts of each form depending on the physiological state of the yeast. The species mainl... |
The plasma membranes phospholipase A2 studied in situ shows very little sensitivity for pH variations ; the optimal concentration for Ca++ is 5 mM ; the enzymatic kinetics are of the Michaelis type. An inactive state of the phospholipase A2 exists : when rats are injected with heparin, their plasma membranes contain a ... |
The sensitivity of the phosphate transport system to pCMPS after phosphate starvation is dependent on protein synthesis. This fact is related to the development of transport activity at alkaline pH. In non-starved cells, the presence of only one peak of maximal activity for phosphate uptake at neutral pH (at low and hi... |
1. Rat liver mitochondrial D(-)-beta-hydroxybutyrate dehydrogenase (submitochondrial particles and partially purified preparation) is inhibited by some dicarboxylates, especially by malonate and succinate. The inhibition is reversible and competitive with beta-hydroxybutyrate while uncompetitive with acetoacetate, NAD ... |
Commercial aqueous 25% glutaraldehyde solutions contain no stable derivative of this aldehyde, but compounds of variable molecular weight which easily revert to glutaraldehyde. The effect of pH on the reaction of glutarldehyde with amino acids and on the stability of the products under acid conditions, shows the import... |
Three protein kinases Ko, K1, and KII have been extracted from rat pancreas homogenate, Ko is not stimulated by cyclic AMP. K1 is poorly stimulated by cyclic AMP (1.3 times), Ku is highly stimulated (6 times). The specificity of KII with respect to various nucleotides and cyclic nucleotides has been determined. K1 and ... |
Various membraneous fractions prepared from a cauliflower homogenate synthesize radioactive oleic acid when they are incubated in a 14C-decanolate solution. The more active fraction is formed of vesicles sedimenting at 30,000 g x 20 mn (heavy microsomes). The labelled precursor is transformed by this fraction mainly in... |
Interaction of usual effectors with acetylcholinesterase (EC 3.1.1.7) from bovine erythrocytes was examined under conditions of high ionic strength (gamma/2 greater than or equal to 0,1). Detailed kinetic investigation of the hydrolysis of acetylcholine by acetylcholinesterase in the presence of modifiers shows that th... |
Kinetic studies of ethanolaminephosphate-cytidylyltransferase (E.C. 2.7.7.14) from rat liver have been carried out in presence of structural analogues of ethanolaminephosphate : these compounds acted as inhibitors of the enzyme: - 2-aminoethylphosphonate behaved as a substrate and a competitive inhibitor to phosphoryle... |
L-aromatic aminoacid decarboxylase has been purified more than thousand times from homogenates of rat brain, in several steps : centrifugation, DEAE-cellulose, CM cellulose, hydroxylapatite, DEAE sephadex. Its properties have been studied, most of them on an intermediate fraction of the purification, because of the ins... |
The digestive juice of Achatina balteata, a giant snail of the West African Coast catalyses the hydrolysis of several natural and synthetic compounds. Enzymatic activities on lactose, o- and p-nitrophenyl-beta-D-galactoside, p-nitrophenyl-beta-D-glucoside, p-nitrophenyl-beta-D (and alpha-L-) fucoside, o-nitrophenyl-bet... |
Ovine anterior pituitary glands contain mannosyl- and fucosyl-transferases localized in the microsomes and able to incorporate mannose or fucose as such from GDP-mannose or GDP-fucose into endogenous glycoproteins. The requirements and conditions necessary for maximum activity were investigated. The value of the Km is ... |
Water-soluble substances have been extracted from two strains of Mycobacterium tuberculosis var. hominis: the native hydrosoluble part (polysaccharide and peptidoglycan), a substance in which the polysaccharide moiety is less abundant than in the latter, the acetylated peptidoglycan and, finally a tetrasaccharide-hepta... |
Arylsulfatase A and B activities were assayed in leucocytes of 43 controls, 11 cases of Metachromatic Leucodystrophy and 7 parents or siblings of patients, using a new technique implying specific inhibitors for leucocyte enzymes. Heterozygotes can be determined, with a 50% value compared to the control, in variant B. E... |
To investigate the thymus-dependent immune competence of Peyer's patches, the course of splenomegaly and hepatic perivascular infiltration (PVI) was studied as criteria of graft-versus-host reaction (GvhR). Parental or F1 hybrid lymphoid tissues, were intrahepatically implanted and the ability of Peyer's patches to ind... |
The sterol compositions of three oceanic jellyfish have been determined using gas chromatographic mass spectrometric techniques involving the use of two separate gas chromatographic column systems. The components in overlapping peaks have been identified by comparison of the mass spectra of peaks in the two column syst... |
The methyl ester of trifluoroacetic acid was prepared by reaction with N,N'-dimethylformamide dimethylacetal and was successfully passed through a gas chromatograph. Trifluoroacetic acid was detected by the use of gas chromatography and low and high resolution gas chromatography mass spectrometry in an acidic extract o... |
The graft versus host reaction (GVHR) was induced in mouse females-hybrids F1 (CBA X C57BL/6) by intravenous injection of suspension of the lymphoid cells of the spleen and of lymphoid nodes from C57BL/6 mouse females. Pregnancy resulted from interbreeding of the test females with syngenic males 1--5 days before, and 1... |
Gamma-glutamyl transpeptidase transfers the gamma-glutamyl moiety of glutathione to a variety of acceptor amino acids. Through the operation of the gamma-glutamyl-cyclotransferase cycle, this enzyme has been implicated in the transport of amino acids into cells, especially the cells of the proximal tubules of kidney. I... |
Quantitative ristocetin-induced platelet aggregation of normal platelet-rich plasma (PRP) decreased with time after PRP preparation. An increase in p H of the PRP with time proved to be responsible for this finding. Diffusion of CO2from the plasma is the prime determinant of the change in pH. Since a complex combinatio... |
Authors report a very rare malformation of the external genital organs in a male new-born who died 48 hours after birth. This malformation consisted in a total aplasia of the corpus cavernosum and bulbus penis with a fusiforme dilatation of the anterior urethra. The malformation was associated with an anal imperforatio... |
1 The antipsychotic drug, clozapine, lowered noradrenaline and metaraminol (MA) concentrations in the rat heart. This action was blocked by the presence of a ganglionic blocking drug. 2 Other alpha-adrenoceptor blocking drugs (phenoxybenzamine, phentolamine) did not significantly lower heart amine concentrations. An in... |
The antiulcer and antisecretory activity of 2-chloro-10-[4'(N-beta-hydroxyethyl) piperazinyl-1'] acetylphenothiazine (SAS) has been investigated. At 10 and 20 mg/kg (s.c.) the drug was found to possess potent antigastric secretory and antiulcer activity (both in shay and stress ulcers) and did not exhibit any periphera... |
Histamine (10 mug/min for 3 min) infused into the brachial artery caused an increase in forearm blood flow which was reduced by mepyramine (25 mg). This effect was most marked in the first minute of the infusion. Metiamide (25 mg) had no effect on the dilatation during the infusion but caused a quicker return of flow t... |
In a double blind trial, 50 male chronic alcoholic patients were treated with either fenfluramine in a dose of 60 mg or 120 mg daily, or with identically prepared placebo tablets. Patients were interviewed on admission to the trial and then at four-weekly intervals for a period of one year and blood levels of delta-ami... |
A rational approach to the use of monoamine oxidase inhibitors (MAOIs) is outlined. Patients suitable for treatment cannot be classified adequately using conventional diagnostic labels. They include those with primary symptoms of hypochondriasis, agoraphobia and social phobias, irritability, somatic anxiety and anergia... |
Gammaglutamyl transpeptidase is an enzyme primarily located in the brush border of the proximal convoluted tubules of the kidney. Its unique localisation in the renal cells most easily damaged by ischaemia and its ease of assay provides the rationale for its use in the measurement of renal ischaemic injury. Using a sta... |
A woman with an intracellular killing defect in the neutrophils had neutrophil pyruvate kinase deficiency. She had had recurrent staphylococcal infections throughout her life. The enzyme present was unstable and its kinetics were abnormal. |
Tyrosine hydroxylase and dopamine-beta-hydroxylase have been measured in 34 discrete areas and nuclei of the limbic system of the rat. Both enzymes showed an uneven distribution in this system. The ratio between tyrosine hydroxylase and dopamine-beta-hydroxylase activities showed a significant correlation when compared... |
The phosphate releasing activity from calf scapula cartilage was resolved by DEAE-cellulose chromatography into two distinct phosphatase activities. The activity eluted first from the column (phosphatase I) was active towards a variety of phosphate esters and several linear oligo phosphates including sodium pyrophospha... |
Using radioactive substrate, thin-layer chromatography and recrystallization methods as well as differential centrifugation, gel filtration and electrophoresis, testosterone metabolism was investigated in male rat epiphyseal growth plate. 5alpha-androstane 3alpha-17beta-diol was found to be a major metabolite in vitro;... |
The cytotoxic action of the antitumor antibiotic mitomycin C occurs primarily at the level of DNA. Using highly sensitive fluorescence assays which depend on the enhancement of ethidium fluorescence only when it intercalates duplex regions of DNA, three aspects of mitomycin C action on DNA have been studied: (a) cross-... |
The reaction of Mucor miehei protease with concanavalin A was followed by a turbidimetric assay in the pH range 5-8. At pH 4.0, no turbidity developed but binding of the enzyme to concanavalin A could be demonstrated by gel filtration. Two fractions of apparent molecular weight 65000 and 52000 were isolated, the 65000 ... |
A sucrase from honey bees (Apis mellifera) which precipitates between ammonium sulfate saturations of 50 and 70% (5 mg protein per millilitre) and which makes up the major portion of the sucrases of honey bees was purified to homogeneity as shown by several criteria. A large part of the sucrase was found in the head wh... |
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