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Citrate synthase activity of Saccharomyces cerevisiae was determined by a radioactive assay procedure and the reaction product, 14C-citric acid, was identified by chromatographic techniques. ATP, d-ATP, GTP and NADH were most inhibitory to the citrate synthase invitro. The activity was inhibited to a lesser extent by A... |
Several aspects of the role of acetate metabolism in the sporulation of Saccaromyces carlsbergensis were investigated. Experiments in which the development of the respiratory system was either stimulated by growth on sugars to which the cells have to adapt, or inhibited by chloramphenicol suggested a correlation betwee... |
The most serious complication of prolonged intravenous infusion of hypertonic dextrose and amino acids is infection. Frequently, the etiology is fungal rather than bacterial. Previous authors have suggested that bacterial survival and growth in the solutions is suppressed by (a) high dextrose concentration, (b) high os... |
A new solid medium is described for growing iron and heterotrophic bacteria from acid mine drainage (AMD). Examination of AMD from five states revealed several kinds of colonies of iron-oxidizing bacteria: (i) smooth, (ii) smooth with secondary growth sectors or branching, (iii) star-shaped, (iv) radiating lobe, and (v... |
The effect of initial pH on aflatoxin production by Aspergillus parasiticus NRRL 2999 was examined in a semisynthetic medium. Maximal growth, aflatoxin production, and aflatoxin production per unit of growth occurred at initial pH levels of 5.0, 6.0, and 7.0 respectively. Initial pH levels less than pH 6.0 favored prod... |
A simple, nonaseptic, low-cast process for the conversion of cassava, a starchy tropical root crop, into microbial protein for use as animal feed was sought. Screening tests culminated in the isolation of a thermotolerant, amylase-producing mold, designated I-21, which was identified as Aspergillus fumigatus. The optim... |
Magnetic filtration was used for the removal of algal populations present in five lakes located in the vicinity of Gainesville, Fla. It was found that the use of this technique enabled a good removal (94%) of algal cells from three lakes where the pH was around 7. The other two lakes, with a higher pH, displayed a lowe... |
Most-probable-number (MPN) and membrane filtration (mF) techniques were evaluated with respect to selectivity, sensitivity, and efficiency in recovering Pseudomonas aeruginosa strains in hospital fluids and extramural water environments. Known numbers of cells of a naturally occurring strain of P. aeruginosa maintained... |
Sporeformers isolated from a commercially canned food were identified as Bacillus cereus, lactose-positive variants. The thermal resistance of spore crops produced from each of two representative cultures was determined in 0.067 M phosphate buffer at pH 7.0. The D121.1 values for one isolate were approximately 0.03 min... |
The kinetic study of a process is usually performed by measuring a convenient intensive property, P, as a function of time. The "affinity rule" states that, when a given process takes place under different external constraints (e.g., different temperatures, pressures, pH values, etc.), the various P versus time curves ... |
Eighteen children suffering from hay fever were treated with intra-nasal beclomethasone dipropionate (400 mug/day) and an identical placebo aerosol in a double-blind cross-over trial. 17 of the children preferred the intranasal beclomethasone dipropionate, one had no preference, none preferred the placebo. The effect o... |
In an intact animal or patient, any shift in oxyhemoglobin affinity is inevitably associated with concurrent fluctuation in numerous other determinants of oxygen delivery. For this reason, the influence of hemoglobin affinity for oxygen on tissue oxygen consumption has been incompletely evaluated. The purpose of this s... |
The relationship between muscle surface pH (pHM) and the arterial-venous oxygen content difference (AVO2D) was studied in 4 patients undergoing reconstructive arterial surgery and in 6 patients undergoing acute normovolemic hemodilution. There was a consistent inverse relation between pHM in the ischemic lower extremit... |
Blood flow in aortocoronary saphenous vein grafts was studied in response to intragraft injection of sodium nitroprusside and papaverine hydrochloride. Following injection of 50 mug of sodium nitroprusside, mean graft flow increased from 40.1 +/- 4.5 to 81.3 +/- 8.5 ml per minute. Administration of 30 mg of papaverine ... |
The comparative in vivo performance of adult-size bubble and rotating membrane oxygenators was evaluated during closed-chest cardiopulmonary bypass for six hours in two groups of dogs. The results show that the rotating membrane oxygenator is efficient in oxygen and carbon dioxide transfer with minimal trauma to blood,... |
The specificity of Ca++ for the interaction of beta adrenergic agonists with their receptors in rabbit right atrial muscle was evaluated. This was accomplished by substituting Ca++ by an equimolar concentration of Sr++. Dose-response curves which demonstrate the effect of norepinephrine and isoproterenol on the rate of... |
A dog liver preparation in situ was used. Intravenous infusion of isoprenaline caused a decrease of plasma potassium levels, which was preceded, in some of the animals infused with higher doses, by a rise in plasma potassium. Propranolol abolished both these effects of isoprenaline, whereas phentolamine was devoided of... |
Six benzodiazepine derivatives, given alone or in combination with amphetamine, were tested in mice subjected to five 100-trial avoidance sessions in the shuttle-box. All derivatives, execpt bromazepam, showed some facilitating effects on avoidance responding when given alone. Facilitation was particularly evident foll... |
Furosemide (6 mg/kg i.p.) increases the renal excretion of water, osmotic active substances, sodium and chloride in 5 to 33 day old rats more than in adults. The dose-response-relations are the same in rats of all age groups: 6 mg/kg of furosemide i.p. are very effective, an increase in dose to 30-60 mg/kg i.p. is not ... |
The action of a number of compounds able to react with thiols was tested on guinea-pig hearts perfused at constant pressure. The SH reagents used were NaNO2, oxidized glutathione, cystamine, diamide, 1,5-difluoro-2,4-dinitrobenzene, nitroglycerol, sodium nitroferricyanide and HgCl2. 6,6'-Dithiodinicotinic acid, an SH r... |
The adrenergic receptor responses of isolated strips of iris dilator muscle from rabbits were studied. An alpha agonist, norepinephrine and a beta agonist, isoprenaline, were used to assess adrenergic sensitivity before and after pretreatment of tissues with metabolic inhibitors at 22, 29 and 37 degrees C. The metaboli... |
In the isolated preparation from the rabbit thoracic aorta, the affinities of the vasoconstrictor agents phenylephrine and histamine, as well as of the vasodilator beta-sympathomimetic drugs isoprenaline, fenoterol (TH 1165a), terbutaline, and salbutamol under the conditions of temperature increase, triiodothyronine an... |
Pentobarbial, thiopental and the convulsant 5-ethyl-5-(2-cyclohexylideneëthyl) barbituric acid (CHEB) were tested for contractor effect on the isolated lung of the fullfrog at pH 7.0 (7% CO2 and 20 mM HCO3-) and pH 8.4 (0.3% CO2 and 20mM HCO3-). CHEB was a potent contractor, thiopental a feeble contractor, and pentobar... |
The spasmolytic activity of six commonly used benzodiazepines was investigated on isolated guinea-pig ileum preparation. All six substances proved to be non-competitive antagonists of carbachol and barium chloride, the pD'2 values ranging between 3.23 and 4.37 in the presence of either agonist. The significance of thes... |
Nicotine perfused through the coronary circulation of the isolated atropinized cat heart elicits antidromic activity in the cardiac sympathetic nerves. The pattern of discharge varies in a complex fashion with dose. At low concentrations, activity may last up to 10 min, whereas at high doses the antidromic response may... |
Water soluble pig insulin (4 x 10(-8) to 4 x 10(-7) g/ml) produced a marked and long-lasting increase in the contractile force of the rabbit auricle in vitro. Once the maximum effect for a given insulin concentration had been reached, addition of more insulin did not produce any further increase in inotropic effect. In... |
The effects of ionic alterations on the accumulation, distribution and movements of 14C-nicotine in slices from rat brain striatum, hypothalamus, cortex and cerebellum were studied. The uptake of 14C-nicotone is not dependent upon Na+ present in the incubation fluid because a K+-substituted (O-Na+) solution increased t... |
Beta-Adrenergic stimulation with isoproterenol hydrochloride in animals causes an antidiuresis similar to antidiuretic hormone. This investigation was undertaken to determine whether isoproterenol inhibits water diuresis in man. Seven young male volunteers were studied during water diuresis in three phases: (1) water-l... |
Nine sickle cell trait and nine control subjects underwent six-hour ammonium chloride acid loading. Maximal urine osmolality and renal hemodynamics were studied separately. Base line arterial pH, carbon dioxide pressure (Pco2), and [HCO3] were normal and comparable in the two groups. After ammonium chloride loading, ur... |
We evaluated the influence of severe disease in human kidneys (12 patients) on gentamicin sulfate accumulation characteristics in such tissue and compared the results with intrarenal tissue concentration data derived from the study of healthy dogs (54 kidneys) during variation in hydration and urinary pH. Our results i... |
The influence of pH on the growth of transmissible gastroenteritis virus (TGEV) in adult pig thyroid cell culture, and on the stability of the virus was studied. At pH 7.2 and 100 fold higher than those at pH 8.0. The adsorption, penetration and uncoating steps of the viral replicative cycle were shown to be unaffected... |
The degradation of biological activity of virus-induced murine interferon was determined in linear nonisothermal and multiple isothermal tests. The stabilizing effect of pH during heating on interferon in solution was greatest at low pH, such that pH 2 greater than pH 5 greater than pH 7 greater than or equal to pH 9; ... |
Herpes simplex virus was inserted into a preformed stable pH gradient and electrofocused for about one hour. Dextran was used as the density gradient forming agent. Virions banded at pH 4.9+/-0.1 and nucleocapsids at 4.1+/-0.05. About 10-20 per cent of infective virus was recovered. |
The growth of avian infectious bronchitis virus (IBV) in chick kidney cells at different pH values in the range 6.0-9.0 demonstrated that although the virus was released at a much faster rate at the higher pH values the titre tended to drop more quickly. At the acid pH values the virus was released more slowly but reac... |
The characteristics of eugenol for dental use appear to improve with age. Exposure to air and light causes certain chemical and physical changes, but the exact nature of the age improvement requires further elucidation. |
We compared ionic fluxes across human gastric mucosa after instillation of test solutions of isotonic hydrochloric acid alone or containing salicylic acid, or prednisolone or both. Prednisolone produced no alteration in fluxes of H+ and Na+ ions compared with controls. Salicyclic acid induced a significant net loss of ... |
Anesthetized dogs, which had been prepared with lumboadrenal vein cannulae, were intravenously infused with monoamine axidase (alphaETA), tryptophan hydroxylase (pCPA) or tyrosine hydroxylase (alphaMT) inhibitors 30 min prior to exposure to 10% oxygen at ground level. These studies were designed to ascertain the role o... |
1. Renal tubular membranes from rat kidneys were prepared, and adenylate cyclase activity was measured under basal conditions, after stimulation by NaF or salmon calcitonin. Apparent Km value of the enzyme for hormone-linked receptor was close to 1 x 10(-8) M. 2. The system was sensitive to temperature and pH. pH was f... |
Rat liver tyrosine aminotransferase was purified 200-fold and an antiserum raised against it in rabbits. 2. Hepatic tyrosine aminotransferase activity was increased fourfold by tyrosine, twofold by tetracycline, 2.5-fold by cortisone 21-acetate and ninefold by a combination of tyrosine and cortisol administered intrape... |
1. Factors regulating the release of alanine and glutamine in vivo were investigated in starved rats by removing the liver from the circulation and monitoring blood metabolite changes for 30 min. 2. Alanine and glutamine were the predominant amino acids released into the circulation in this preparation. 3. Dichloroacet... |
1. tRNA was extracted from rabbit liver by both the phenol and diethyl pyrocarbonate methods under conditions preventing deacylation of the amino acids attached in vivo. 2. After deacylation 12 amino acids were determined by gas-liquid chromatography, by using the flame-ionization and nitrogen-sensitive thermionic dete... |
An "inhibitor-stop" technique has been developed for measuring initial rates of pyruvate transport into mitochondria. The technique uses alpha-cyano-3-hydroxycinnamate as the inhibitor and separates the mitochondria from the radioactive medium by Millipore filtration. Observed rates depend on availability of hydroxyl a... |
A chondroitinase that degrades only chondroitin sulphate B was isolated from Flavobacterium heparinum, and separated from a constitutive chondroitinase AC also present in extracts of F. heparinum. The enzyme acts only on chondroitin sulphate B, producing oligo- and tetra-saccharides, plus an unsaturated 4-sulphated dis... |
A method was developed which involved electroimmunoassay and crossed immunoelectrophoresis of subtilopeptidase A (EC 3.4.21.14). Initial trials with unfractionated antiserum were not successful and interaction of the enzyme with non-immunoglobulin serum components were shown to be the cause of the failures. Quantitativ... |
The rate of oxidation of ferricyanide of the aldolase-dihydroxyacetone phosphate complex was measured under different conditions. The following conclusions are drawn. 1. In the cleavage of fructose diphosphate, catalysed by native aldolase, the steady-state concentration of the enzyme-dihydroxyacetone phosphate carbani... |
A collagenase was purified from homogenates of V2 ascites-cell carcinoma growing in rabbit muscle. (NH4)2SO4 precipitation, ion-exchange and gel-filtration chromatography, and affinity chromatography (by using the CB7 CNBr) cleavage fragment of alpha 1(I) collagen linked to agarose) gave a 268000-fold purification and ... |
1. A lysosomal fraction was separated by density-gradient centrifugation from a highly purified human polymorphonuclear leucocyte suspension. 2. Some 23 different lysosomal enzymes were assayed for activity in the presence of various concentrations of glycosaminoglycans. 3. The 21 acid hydrolases assayed were strongly ... |
Serum prolactin concentrations were measured by radioimmunoassays in 98 patients with established carcinoma of breast, 12 patients with cystic mastitis and 10 patients with gynaecomastia and compared with that of age matched normal control women. The serum prolactin levels in the patients with breast cancer, gynaecomas... |
The effect of a single interaperitoneal injection (6 mg/kg body weight) of aflatoxin B1 in propylene glycol on pyridine nucleotides and NDP linked dehydrogenases was studied 24 h after administration of the toxin. The liver showed a decrease in total proteins and pyridine nucleotides though levels of NADP and NADPH rem... |
The hydrolysis of a series of depsipeptides demonstrates that the zinc neutral endopeptidases of bacteria are active esterases. Esters such as BzGly-OPhe-Ala, BzGly-OLeu-Ala, and FA-Gly-OLeu-NH2 are hydrolyzed at rates three- to eightfold slower than are their exact peptide analogues, when hydrolyzed by thermolysin, Ba... |
Citrate synthase from Escherichia coli enhances the fluorescence of its allosteric inhibitor, NADH, and shifts the peak of emission of the coenzyme from 457 to 428 nm. These effects have been used to measure the binding of NADH to this enzyme under various conditions. The dissociation constant for the NADH-citrate synt... |
3-Dimethylamino-1-propyne irreversibly inactivates mitochondrial monoamine oxidase from bovine liver. The inactivation results in the loss of absorption in the 450-500-nm region of the flavine spectrum and a concomitant increase in absorbance at 410 nm. For the enzyme-bound adduct epsilon410 = 28000. The spectral prope... |
Radioactive carbon-14 L-alpha-aminoadipic acid, L-cysteine, or L-valine were readily incorporated into the intracellular tripeptide, delta-(alpha-aminoadipyl)cysteinylvaline (ACV), by washed starved cells of Penicillium chrysogenum. The labeled ACV in each case was oxidized with performic acid and isolated as its corre... |
A chromatin-bound protease, active in 2 M NaCl-5 M urea or 5 M urea alone, was demonstrated in rat liver, kidney, testes, brain, rabbit bone marrow, chicken reticulocyte, and Ehrlich ascites chromatin. Chicken erythrocyte chromatin did not possess any detectable proteolytic activity in salt and urea. The proteolytic ac... |
A simple procedure for the purification of Mg2+-stimulated ATPase of Escherichia coli by fractionation with poly(ethylene glycols) and gel filtration is described. The enzyme restores ATPase-linked reactions to membrane preparations lacking these activities. Five different polypeptides (alpha, beta, gamma, delta, epsil... |
The conformation of the gonadotropin releasing hormone (Gn-RH), whose primary sequence is pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-GlyNH2, and of several of its structural analogues has been studied by circular dichroism, optical rotatory dispersion, and fluorescence spectroscopy. The effects of pH, guanidine, and temperat... |
The pH dependence of the nuclear quadrupole interaction between the excited 247-keV state in 111Cd bound to the active site in human carbonic anhydrase B and the nearest protein surroundings has been studied by means of the nuclear spectroscopic technique of perturbed angular correlation of gamma rays. The enzyme has b... |
The oxidation-reduction properties of the high potential iron-sulfur protein (HIPIP) from Chromatium vinosum have been investigated. Both equilibrium and kinetic measurements demonstrate electron transport by HIPIP is pH independent in the pH range 7-11. The kinetics of reduction (potassium ferrocyanide, SO2, S2O42-, s... |
A method of isolation of alpha-1-antitrypsin (alpha-1-AT) in good yield from normal human plasma is described. A key step was affinity chromatography employing an antiserum which had been depleted of alpha-1-AT antibodies. The final preparations were homogeneous by immunological and physicochemical criteria. The specif... |
An acid protease produced by the thermophilic fungus Penicillium duponti K 1014 has been purified by consecutive ion-exchange and gel permeation chromatography, and crystallized from aqueous acetone solution. The purified endopeptidase gave a symmetrical schlieren peak by sedimentation velocity, and was found to be hom... |
The Escherichia coli B glycogen synthase has been purified to apparent homogeneity with the use of a 4-aminobutyl-Sepharose column. Two fractions of the enzyme were obtained: glycogen synthase I with a specific activity of 380 mumol mg-1 and devoid of branching enzyme activity and glycogen synthase II having a specific... |
Bovine procarboxypeptidase A exhibits intrinsic hydrolytic activity toward haloacyl amino acids (Behnke and Vallee, 1972), as well as toward conventional peptide and ester substrates for carboxypeptidase A (Bezzone, 1974; Uren and Neurath, 1974). The kinetics of hydrolysis of a series of such substrates by native proca... |
The ionization and phase behavior of 1,2-dipalmitoyl-sn-glycero-3-phosphoserine have been investigated under a variety of condtions by several different methods. As measured by turbidity changes, the temperature of the crystal-liquid crystal phase transition of this lipid is influenced by pH and mono- and divalent cat... |
The intensity of light scattering from suspensions of membrane fragments prepared by sonication of beef heart mitochondria in the presence of EDTA at alkaline pH (ESMP) was determined at 45, 90, and 135 degrees with light of wavelength 546 nm. The dissymmetry ratio Z = I45 degrees c/I135 degrees c, where I45 degrees c ... |
Treatment of calf serum at 60 degrees C and pH 3.5 followed by chromatography on carboxymethyl (CM) cellulose resulted in the separation of two major peaks of alkaline RNAse activity. One was eluted from CM-cellulose at 0.075 M KCl with an overall purification of 5400-fold and the other was eluted at 0.25 M KCl with a ... |
A renal brush border fraction was isolated from newborn Sprague-Dawley rats, and its morphological and enzymatic characteristics were studied in comparison to that from the adult. Definite microvillar structures are seen by electron microscopy, and border preparations from the newborn are enriched in known marker enzym... |
Compared with human material glial fibrillary acidic protein isolated from bovine, rat and mouse brain was remarkably homogeneous and migrated as a single band at 54 000 mol. wt. on sodium dodecyl sulfate gel electrophoresis. The protein was extremely susceptible to proteolysis and lower molecular weight components wer... |
1. Gel electrofocusing followed by gel gradient electrophoresis separated the haptoglobins and their complexes with haemoglobin into characteristic two-dimensional patterns of protein bands. 2. Molecular weights of 107 000, 139 000 and 168 000 were obtained for the three bands seen after a purified preparation of hapto... |
Mössbauer spectroscopy has been used to study the heme iron in various states of cytochrome P450cam from the camphor-hydroxylating system of the bacterium Pseudomonas putida. Native, camphor-free P450cam contains low-spin ferric iron, part of which (approx. 50-70%) is converted to the high-spin ferric state upon additi... |
Enolase from bakers' yeast was separated into three isoenzymes by countercurrent distribution. The isoenzymes were partitioned in aqueous polymer two-phase systems containing positively charged trimethylamino poly(ethylene glycol) or negatively charged poly(ethylene glycol) sulphonate. The plots of the partition coeffi... |
The need for chaotropic eluents in immunoaffinity chromatography is a consequence of the high affinities of antibodies towards their antigens. This affinity is decreased and elution of antiglucagon antibodies from a column of immobilized glucagon can be achieved under mild conditions when the steric complementarity to ... |
A sedimentable form of acid phosphatase (EC 3.1.3.2) from Tetrahymena pyriformis was found to be solubilized by Triton X-100. The total enzyme activity in the insoluble cell fraction increased almost 200% upon solubilization with Triton X-100 or Nonidet P-40. Removal of membrane lipids and Triton X-100 from the particu... |
The inactivation of the neurohypophyseal hormones arginine vasopressin and oxytocin, both 14C-labelled in the C-terminal glycine residue, by enzymes present in kidney homogenates of various species has been investigated, and some of the enzymes responsible have been partially purified and characterized. The Leu-Gly pep... |
Adenosine phosphorylase (EC 2.4.2.-) activity present in Sarcoma 180 cells grown in culture and in rat liver, is shown to be distinct from inosine-guanosine phosphorylase by several criteria: (a) treatment of Sarcoma 180 cell extract with p-chloromercuribenzoate inhibited the two activities to a different extent, (b) a... |
Four inhibitors of alpha-amylase (EC 3.2.1.1) were separated from an alcohol extract of wheat by ion-exchange chromatography on DE52-cellulose. One inhibitor, which showed the greatest specificity for human salivary amylase relative to human pancreatic amylase, has been purified by the following steps: (a) alcohol frac... |
Prolyl dipeptidase (iminodipeptidase, L-prolyl-amino acid hydrolase, EC 3.4.13.8) was purified 180-fold from bovine kidney. The enzyme which was obtained in a 10% yield was completely separated from a number of known kidney peptidases including an enzyme of very similar substrate specificity, proline aminopeptidase (L-... |
A procedure is described for the preparation of extensively purified beta-D-glucosidase (EC 3.2.1.21) from the cytosol fraction of rat kidney. The specific activity of the beta-glucosidase in the high speed supernatant (100 000 X g, 90 min) fraction of rat kidney homogenate is 700-fold greater than that in the same fra... |
Phosphorylation of NaI-treated bovine brain cortex microsomes by inorganic phosphate in the presence of Mg2+ and ouabain has been studied at 0 degrees C (pH 7.4) and 20 degrees C (pH 7.0). Nearly maximal (90%) and half-maximal phosphorylation are achieved at 20 degrees C within 2 min with 50--155 and 5.6--17 muM 32Pi, ... |
A phosphoprotein kinase (EC 2.7.1.37) KIVb, from rat liver nuclei, was purified 75-fold by phosphocellulose chromatography and gel filtration on Sephadex G-200. The enzyme, which has an apparent molecular weight of 55 000, phosphorylates casein and chromatin-bound nonhistone proteins more readily than histones or ribos... |
Cysteine oxidase (cysteine dioxygenase, EC 1.13.11.20) was purified approximately 1000-fold from rat liver. The purified enzyme (protein-B) was obtained as an inactive form, which was activated by anaerobic preincubation with L-cysteine. The active form of protein-B was inactivated during aerobic incubation to produce ... |
1. The technique of differential thermal and proteolytic inactivation has been employed as a conformational probe for the lysine-sensitive aspartokinase (EC 2.7.2.4) of Escherichia coli B. 2. L-Amino acid inhibitors of this enzyme each induce a characteristic enzyme conformation. This is evidenced by rates of thermal a... |
Weight-average elution volumes of sulphatase A (an arylsulphate sulphohydrolase, EC 3.1.6.1) from Sephadex G-200 have been determined as functions of protein concentration, pH, ionic strength and temperature. The results are used to calculate the apparent association equilibrium constants for tetramer formation and the... |
A D-galacturonanase (EC 3.2.1.67) catalyzing the degradation of D-galacturonans by terminal action pattern was purified from a culture filtrate of Aspergillus niger by a procedure including the salting-out with ammonium sulfate, precipitation by ethanol, chromatography on DEAE-cellulose, and gel chromatography on Sepha... |
The cyanobacteria produce multi-L-arginyl-poly (aspartic acid), a high molecular weight (Mr=25 000-125 000) branched polypeptide consisting of a poly(aspartic acid) core with L-arginyl residues peptide bonded to each free carboxyl group of the poly(aspartic acid). An enzyme which will elongate Arg-poly(Asp) has been is... |
Counter-current distribution in an aqueous Dextran-polyethylene glycol two-phase system has been used to fractionate membrane fragments obtained by press treatment of Class II chloroplasts. By the counter-current distribution technique membrane particles are separated according to their surface properties such as charg... |
The relationship between proton movement and phosphorylation in Halo-bacterium halobium R1 has been investigated under anaerobic conditions. The light-induced changes in the bacteriorhodopsin are accompanied by proton movements across the membrane which result in pH changes in the suspending medium. The initial alkalin... |
1. Addition of succinate to valinomycin-treated mitochondria incubated in KCL causes a large electrolyte penetration. The process depends on a steady supply of energy and involves a continuous net extrusion of protons. Rates of respiration and of electrolyte penetration proceed in a parallel manner. 2. A passive penetr... |
The treatment of spinach chloroplasts with p-nitrothiophenol in the light at acidic and neutral pH'S caused specific inhibition of the Photosystem II activity, whereas the same treatment in the dark did not affect the activity at all. The photosystem I activity was not inhibited by p-nitrothiophenol both in the light a... |
The transmembrane electrical potential (deltaphi), the proton flux (H+), the rate of electron transport (e), the pH gradient (deltapH) and the rate of phosphorylation (ATP) were measured in chloroplasts of spinach. Photosynthesis was excited periodically with flashes of variable frequencies and intensities. A new metho... |
A simplified system, consisting of NADPH, Fe3+-ADP, EDTA, liposomes, NADPH-cytochrome c reductase and Tris - HCl buffer (pH 6.8), has been employed in studies of the generation of singlet oxygen in NADPH-dependent microsomal lipid peroxidation. The light emitted by the system involves 1deltag type molecular oxygen iden... |
Prompt and delayed chlorophyll fluorescence have been studied in broken spinach chloroplasts at pH values down to 2.6. No direct effect of low pH on the primary charge separation in Photosystem II was observed. The irreversible inactivation of a secondary electron donor in a narrow pH range around pH 4.5 was demonstrat... |
In a number of animal species soluble NADH-cytochrome b5 reductase of erythrocytes was compared with membrane-bound NADH-cytochrome b5 reductase of liver microsomes by using an antibody to purified NADH-cytochrome b5 reductase from rat liver microsomes. The results obtained indicated clearly that they are immunological... |
The effect of NADP+ on light-induced steady-state redox changes of membrane-bound cytochromes was investigated in membrane fragements prepared from the blue-green algae Nostoc muscorum (Strain 7119) that had high rates of electron transport from water to NADP+ and from an artificial electron donor, reduced dichlorophen... |
1. Techniques and experiments are described concerned with the millisecond kinetics of EPT-detectable changes brought about in cytochrome c oxidase by reduced cytochrome c and, after reduction with various agents, by reoxidation with O2 or ferricyanide. Some experiments in the presence of ligands are also reported. Lig... |
We have examined the bacteriochlorophyll reaction-center complex of Chlorobium limicola f. thiosulfatophilum, strain Tassajara. Our results indicate that the midpoint potential of the primary electron donor bacteriochlorophyll of the reaction center is +250 mV at pH 6.8, while that of cytochrome c-553 is +165 mV. There... |
The rates and equilibria for the addition of sodium bisulfite to uracil, thymine, and their nucleosides have been studied for the pH range 3-9.5. The rate of addition for uracil is proportional to the concentration of sulfite ion and unionized uracil. The equilibrium constant (25 degrees C) for the reaction is (1.0 +/-... |
Physicochemical properties of mixtures of spectrin and actin extracted from human erythrocyte ghosts have been correlated with ultrastructural changes observed in freeze-fractured erythrocyte membranes. (1) Extracted mixtures of spectrin and actin have a very low solubility (less than 30 mug/ml) near their isoelectric ... |
Calcium transport into sarcoplasmic reticulum fragments isolated from dog cardiac and mixed skeletal muscle (quadriceps) and from mixed fast (tibialis), pure fast (caudofemoralis) and pure slow (soleus) skeletal muscles from the cat was studied. Cyclic AMP-dependent protein kinase and phosphorylase b kinase stimulated ... |
Enthalpy of the association of trypsin with pancreatic inhibitor from bovine pancreas at 25 degrees C as a function of pH and ionic strength is estimated. The dependence of the enthalpy on pH is of an extremal character with a minimum at pH 7.6 (delta H degrees =-10.3 ccal/mole). The increase of ionic strength with the... |
11-Fold purified protease preparation is isolated from cultural medium of Torula thermophila UzPT-1 by means of ammonium sulphate precipitation and gel chromatography through Sephadex G-100. Disc polyacrylamide gel electrophoresis revealed two portease components, one of them possessing proteolytic activity. pH interva... |
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