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Results for “OXIDATION-REDUCTION”

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At least 1,063 records · Page 59Linked to original sources
PubMed1975

3alpha-Reduction of dihydrotestosterone in human normal and hypertrophic prostatic tissues.

The activity of 3alpha-reduction of dihydrotestosterone was located in both the particulate and the soluble fractions of human prostatic tissues. Activity of 3alpha-reduction was higher than that of 3beta-reduction under the incubation conditions employed; therefore, the main reductive metabolic pathway of dihydrotestosterone seemed to be the formation of 5alpha-androstane-3alpha,17beta-diol in human prostatic tissues. There was no significant difference between normal and hypertrophic prostatic tissues when the activity of 3alpha-reduction of dihydrostertosterone was compared on a wet weight basis.

Aged↗
PubMed1975

[Conditions of periodic oxidation in the determination of the fluorescent PAS reaction].

The effect of temperature, pH, and concentration of potassium periodate solution on the intensity of fluorescence PAS-reaction was studied. The reaction was shown to be most specific in respect to glycogen at the temperature of oxidizer 4 degrees C (optimal time of oxidation being 10-12 hr). Similar results were also obtained at 20 degrees (optimal time of oxidation being 1.5 hr). Under these conditions the curve of dependence of the reaction intensity on the time of auramine-SO2 treatment double-stepped character which can be due to the presence of two glycogen fractions in hepatic cells. The fluorescence PAS-reaction intensity varied in significantly when the periodate concentration changed from 0.8 to 1.2% (from 0.2 to 0.8%) it gradually increased and pH -from 2.0 to 6.0.

Animals↗
PubMed1975

Luminescence and respiratory activities of Photobacterium phosphoreum. Competition for cellular reducing power.

Changes in the in vivo luminescence, respiratory activities, contents of cytochromes, extractable luciferase and NAD(P)H-FMN reductase during growth of the wild (bright) strain of Photobacterium phosphoreum and its dim mutant were determined. The intensity of the in vivo luminescence per cell increased 10 times in the wild strain and 750 times in the dim strain during logarithmic growth, while the contents of luciferase and NAD(P)H-FMN reductase remained almost constant. It is suggested that a characteristic change in the mode of competition of the luminescence reaction system with another electron transfer chain involving cytochromes for NAD(P)H take place during the growth of this bacterium.

Cell Division↗
PubMed1976

Pulse radiolytic investigation of single heme group reduction in hum an methemoglobin.

Reduction of one of the four heme groups of human aquomethemoglobin A has been investigated by the pulse radiolysis method. The reactivity of e-a-q, the hydrated electron, with methemoglobin was determined by observing this species directly. The separate reactions of the hydroxy yl radical and hydrogen atom, as well as of e-a-q, were studied by observing absorbance changes in the protein spectrum over the wavelength range 290 to 600nm, with appropriate scavengers in solution...

Azides↗
PubMed1975

Cytogenetics analysis of meiotic chromosomes of irradiated mice and their progeny after treatment with streptomycin and dihydrodeoxystreptomycin.

The purpose of this investigation is to find out whether streptomycin and the related compound dihydrodeoxystreptomycin have any mutagenic effect and whether they both are capable of recovering X-ray induced chromosomal translocations in mouse spermatogonia of directly treated animals and their progeny of the first generation. The cytological findings show the absence of any mutagenic effect in animals nonirradiated and treated with streptomycin and dihydrodeoxystreptomycin. The frequency of chromosomal translocation after total irradiation was 9,07%; in animals treated with streptomycin following irradiation 5.13%, and in those irradiated and treated with dihyrodeoxystreptomycin, 3.70%. Male offsprings, originated from parents treated only with antibiotics show no chromosomal translocations. However, offsprings originated from irradiated and treated parents gave birth to the male offspring with chromosomal translocations.

Animals↗
PubMed1975

Early changes in myocardial hypoxia: relations among mechanical function, pH, and intracellular redox states.

When rat hearts were subjected to abrupt hypoxia the onset of NADH changes as measured by epicardial fluorescence and of depressed contractility occurred at similar times. Direct measurements of changes in tissue metabolism lagged behind changes in fluorescence and contractility. Calculated NAD:NADH ratios became reduced more rapidly and to a greater extent in the cytoplasm than in the mitochondria, but did not necessarily signal greater changes in total NADH. The detection of depressed contractility before a fall in intracellular pH or a rise in intracellular lactate casts doubt on the postulate that an increase in hydrogen ion is the primary cause of hypoxic myocardial failure.

Animals↗
PubMed1976

[Zincporphyrin pigments in the botryoid tissue of Haemopis sanguisuga L. and their localization by diaminobenzidine-H2O2 reaction (author's transl)].

From isolated botrydiosomes of Haemopis sanguisuga L. a pigment was extracted, separated by preparative paper chromatography and analysed chemically. Chromatographically the pigment was found to be composed of two fractions, which has been identified as zincporphyrin compounds, which are able to oxidize of diaminobenzidine in the presence of H2O2. As proved by ultrahistochemical method, the product of hte diaminobenzidine-H2O2 reaction is associated in the botryoid cells with the tubules foth of the endoplasmic reticulum and of botrydiosomes. The proboble functions of the zincporphyrins in the oxidizing processes are discussed.

3,3'-Diaminobenzidine↗
PubMed1976

Amino acid metabolism and protein synthesis in streptomycin resistant Vibrio El Tor.

Metabolic activities in relation to protein synthesis and amino acid utilization are altered in Vibrio El Tor after development of resistance towards streptomycin. Efficiency of in vivo and in vitro protein synthesis is markedly reduced in streptomycin resistant Vibrio El Tor. The rate of incorporation of 14C-amino acids into protein, uptake of 14C-valine and oxidation of certain amino acids are also altered.

Amino Acids↗
PubMed1976

Studies on platelet plasma membranes. I. Characterization of surface proteins of human platelets labeled with diazotized (125i)-diiodosulfanilic acid.

A polar, nonpenetrating compound of high specific activity, diazotized (125I)-diiodosulfanilic acid (DD125ISA), has been developed as a label for exposed proteins of the human platelet plasma membrane, and platelet proteins and the pattern of labeling have been studied with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). That DD125ISA binds specifically to membrane proteins was demonstrated by: (1) the specific activity of isolated membrane protein was five to seven times that of whole platelet protein and (2) no proteins of intact platelets were labeled which were not represented in the isolated plasma membrane. That the DD125ISA-labeled membrane proteins were exposed on the cell surface was demonstrated by: (1) DD125ISA-labeled proteins were altered by trypsin treatment of intact, labeled platelets and (2) the pattern of labeling produced by reaction of isolated membranes with DD125ISA was quite different from that produced by the labeling of intact platelets. Analysis of platelet membrane proteins by SDS-PAGE demonstrated the glycoproteins previously described at 150,000 daltons (termed glycoprotein I) and 92,000 daltons (glycoprotein III) but we could discriminate two apparently distinct glycoproteins in the intermediate region (IIa: 125,000 daltons, and II: 118,000 daltons). Glycoproteins I and III were constant whereas IIa was clearly visible only in unreduced samples and II was predominant in reduced samples. Reaction of DD125ISA with intact platelets resulted in equal labeling of three of these four membrane glycoproteins (IIa, II, and III). The pattern of exposed proteins on the platelet surface labeled by DD125ISA was different from lactoperoxidase-131I, which labeled predominantly the 92,000 dalton glycoprotein, as demonstrated by simultaneous SDS-PAGE analysis. Therefore three glycoproteins of the human platelet plasma membrane are exposed to a radioisotope probe on the platelet surface and are accessible for contact interactions.

Azo Compounds↗
PubMedDate not supplied

Oxisuran reduction by rabbit tissue preparations.

Oxisuran, 2-((methylsulfinyl)acetyl)pyridine is reduced to alpha-((methylsulfinyl)methyl-2-pyridinemethanol, oxisuranol, by cytoplasmic enzymes from rabbit liver, kidney, brain, intestine, and lung. The cytoplasmic enzyme from liver is dependent on NADPH as cofactor and has an optimal pH of 6.0. Enzymatic activity is also present in liver mitochondria but at a lower specific activity. The cytoplasmic extracts catalyze the formation of two oxisuranol products, presumably the diastereoisomers described by Di Carlo and associates from in vivo studies. Verification of the product as oxisuranol was accomplished by thin-layer chromatography and mass spectrometry.

Animals↗
PubMed1976

Mechanism of the irreversible inhibition of aspartate aminotransferase by the bacterial toxin L-2-amino-4-methoxy-trans-3-butenoic acid.

The naturally occurring toxin L-2-amino-4-methoxy-trans-3-butenoic (AMB) acid irreversibly inhibits pyridoxal phosphate-linked aspartate aminotransferase. The inhibitor is a substrate for the enzyme, and as such is converted into a highly reactive intermediate which chemically reacts with an active site residue, thus irreversibly inactivating the enzyme. Enzymological and model studies on AMB are presented which enable one to determine the precise mechanism of action of this toxin. The mechanism involves Schiff base formation between the enzyme and toxin followed by alpha-C--H bond cleavage and aldimine isomerization to generate a bifunctional Michael acceptor. This molecule alkylates an active site residue by an addition and elimination route.

Aminobutyrates↗