Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.8.1.4 (diaphorase)
 2,754 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A dihydrodipicolinate reductase containing flavin was purified from sporulating Bacillus subtilis PCI 219. The purified enzyme appeared homogeneous by dise gel electrophoresis. Its molecular weight was estimated as 74,000 by gel filtration on Sephadex G-200, and as 18,500 by electrophoresis on sodium dodecylsulfate polyacrylamid gel. These results suggest that the enzyme is composed of four subunits. The prosthetic group was identified as FMN, and one mole of the enzyme contained two moles of FMN. Both NADPH and NADH acted as coenzyme, though NADH was less effective. The enzyme also exhibited diaphorase activity. The pH optimum was 6.1. The enzyme was inhibited by dipicolinate but not by lysine or alpha, epsilon-diaminopimelate.
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PMID:A new flavin enzyme catalyzing the reduction of dihydrodipicolinate in sporulating Bacillus subtilis I. Purification and properties. 23 91

NADH- and NADPH-diaphorases, 3alpha-, delta5-3beta-, 11beta- and 17beta-hydroxy-steroid dehydrogenases (HSD) and lipids were studied histochemically in the testes and adrenals of male bank voles kept in a long (16L:8D) or a short (8L:16D) photoperiod (Groups L and S, respectively). At 67 days of age the Group L males were heavier and had active and significantly larger testes than Group S males. The testes of Group S males were regressed and were also significantly smaller than those of 18-day-old animals born and reared in a 18L:6D photoperiod. Lipid droplets were detected in the Leydig cells and intratubular spaces in the testes of Group L animals, but were absent from those of Group S voles. The adrenal cortex of the Group L animals was virtually devoid of lipids, but large lipid inclusions were present in the basal zona fasciculata of the Group S voles. In the Group L testes the diaphorase activities were more intense and the difference in enzymic activity between the seminiferous epithelium and the Leydig cells was more pronounced (especially for NADH-diaphorase) than that in the testes of Group S animals. Moreover, the 3alpha-- and delta5-3beta-HSD activities were much stronger in the testes of sexually active animals; 17beta-HSD activity was present in the Leydig cells of the active testes, and absent in the regressed testes. There was no marked difference between the two groups of animals with regard to the distribution or intensity of diaphorases, 3alpha-, delta5-3beta-, 11beta- or 17beta-HSD in the adrenal cortex. It is concluded that a decline in steroid synthesis occurs in the testes of voles kept in a short photoperiod. The large lipid inclusions observed in the adrenal cortex of such animals suggest decreased corticosteroid synthesis and/or secretion.
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PMID:A histochemical study on the effects of photoperiod on gonadal and adrenal function in the male bank vole (Clethrionomys glareolus). 36 52

Thioredoxin from Escherichia coli was shown to catalyze the reduction of insulin disulfides by dithiothreitol. A quantitative assay was developed which measures the rate of insulin reduction spectrophotometrically at 650 nm as turbidity formation from the precipitation of the free insulin B chain. Thioredoxin, at 5 microM concentration, accelerated the reaction between 0.130 mM insulin and 1.0 mM dithiothreitol at pH 7 around 20-fold. The pH optimum of the reaction was 7.5. Thioredoxins from E. coli and calf liver showed similar specific activities. Stopped flow fluorescence measurements of the rate of reduction of thioredoxin-S2 by dithiothreitol showed a second order rate constant of 1647 M-1 s-1 at pH 7.2. This is between 10(2) to 10(3) times larger than the reaction between insulin or linear model disulfides and dithiothreitol. It is consistent with a ping-pong mechanism of thioredoxin catalysis since reduced thioredoxin is known to react very fast with insulin. Thioredoxin also catalyzed lipoamide-dependent reduction of the insulin disulfides in a coupled system with NADH, lipoamide, and lipoamide dehydrogenase. The fast spontaneous reaction between dihydrolipoamide and thioredoxin-S2 provides a mechanism for NADH or pyruvate-dependent disulfide reduction. The implication of the dithiol-disulfide oxidoreductase activity of thioredoxin for the regulation of enzyme activities by thiol oxidation-reduction control is discussed.
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PMID:Thioredoxin catalyzes the reduction of insulin disulfides by dithiothreitol and dihydrolipoamide. 38 88

Cell-free extracts of a streptomycin-bleached strain of Euglena gracilis var. bacillaris have been examined for enzyme systems primarily responsible for the oxidation of reduced pyridine nucelotides. NADH lipoyl dehydrogenase, NADH and NADPH oxidase, NADH and NADPH diaphorase, and NADH and NADPH cytochrome c reductase have been demonstrated. The NADPH-linked enzymes had lower activity rates and were less sensitive to N-ethyl maleimide and p-hydroxymercuribenzoate than their NADH-linked counterparts. NADH cytochrome c reductase was the most sensitive to antimycin A. Michaelis-Menten constants (Km) determined were as follows: NADH diaphorase, 350 muM; NADPH oxidase 150 muM ; NADH lipoyl dehydrogenase, 0.35 muM. Enzyme activities after storage at -5 C indicate that the diaphorases are less labile than the other tested enzymes, and the differential activities of the NADH and NADPH linked enzymes suggest that functionally they may have different roles.
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PMID:Reduced pyridine nucleotide oxidases of Eugena gracilis var. bacillaris. 40 56

(1) Various buffer systems for the starch gel electrophoresis of human diaphorase isozymes have been explored. Electrophoresis in a Tris/Borate system at pH 8.6 which includes 70 micron NADH in the gel and cathodal electrode buffers, provides good resolution of the six DIA3 phenotypes previously resolved by isoelectric focusing. (2) The variant genes DIA13, DIA23 and DIA33 occur with frequencies of about 0.76, 0.23 and 0.01 respectively in the English population. (3) The isozymes determined by the least common gene, DIA33, are markedly different from the isozymes determined by DIA13 and DIA23 in their relatively low heat stability, high affinity for Blue Sepharose and slow anodal electrophoretic mobility in buffer systems containing borate. The DIA3 1 and DIA3 2 isozymes are similar to one another in these characteristics.
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PMID:A comparison of the biochemical properties of the human diaphorase (DIA3) isozymes determined by the common alleles DIA13, DIA23 and DIA33. 43 72

The usual techniques for determination to total 3 alpha-hydroxy bile acids in serum involving liquid-solid extraction of the bile acids with the adsorbent XAD-2 and fluorimetric measurement of NADH generated from the reaction with a NAD-linked 3 alpha-hydroxysteroid dehydrogenase are evaluated and improved. The influence of different types of enzyme preparations on the results is examined. The results with the improved technique are compared to the results obtained with another method, avoiding extraction of the bile acids before the enzymatic reaction which is followed by fluorimetric measurement of resorufin, produced by transfer of the hydrogen of the generated NADH by diaphorase to resazurin. No significant difference between the results with the two types of methods was found. The concentration of total 3 alpha-hydroxy bile acids in serum of 46 fasting 'healthy' individuals aged 17 to 82 years is estimated. 30 were females, of whom 10 were taking estrogen-containing oral contraceptives, and 16 were males. Mean +/- standard deviation in all the females was 3.0 +/- 1.1 micromol/l, and in the males 4.0 +/- 1.9 micromol/l. There was no significant difference between any of the groups.
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PMID:Determination of total 3 alpha-hydroxy bile acids in serum. 43 89

The distribution and activities of several oxidative enzymes in the urinary apparatus of five freshwater fish species (river lamprey, lobe finned eel, Prussian carp, rainbow trout and three-spined stickleback) have been studied. Species were selected from three main taxonomic groups: Cyclostomata, Polypterini, Teleostei. Distinctly positive enzyme reactions were only found in the tubular elements of the kidney and the collecting duct-archinephric duct system, with the exception of the generally weak staining intensities of lactate dehydrogenase. The distal tubule normally showed strong to very strong reactions for most of the enzymes investigated. In the epithelial cells of the collecting tubule-collecting duct system, stronger reactions were observed for most of the mitochondrial-bound enzymes, especially succinate dehydrogenase and NADH-diaphorase. For these enzymes, the cells of the archinephric duct reacted strongly positive in Lampetra, Carassius and Gasterosteus. The enzyme patterns of various types of urinary tubules and ducts are compared with results of several morphological studies. In addition, the histochemical findings are discussed in relation to kidney function in different vertebrate groups.
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PMID:Oxidative enzymes in the urinary apparatus of several freshwater fishes. 43 99

The ovary of the domestic pigeon, Columba livia, has been assayed histochemically for the localization of delta 5-3 beta-hydroxysteroid dehydrogenase (delta 5-3 beta-HSDH), 17 beta-hydroxysteroid dehydrogenase (17 beta-HSDA), 11 beta-hydroxysteroid dehydrogenase (11 beta-HSDH), glucose-6-phosphate dehydrogenase (G6P-DH) and NADH-diaphorase activities during different periods of the reproductive cycle. delta 5-3 beta-HSDH, 17 beta-HSDH, 11 beta-HSDH, G6P-DH and NADH-diaphorase activity was found in the theca interna of growing, atretic and postovulatory follicles, the granulosa of ovulatory, atretic and postovulatory follicles, and interstitial gland cells during the pre-incubation and the laying periods. During the incubation and squab feeding periods only delta 5-3 beta-HSDH, G6P-DH and NADH-diaphorase activities were observed in the above mentioned cells. The steroidogenic potential of atretic follicles depends upon the type of atresia a follicle undergoes.
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PMID:Steroid synthesizing cellular sites in the ovary of the domestic pigeon Columba livia (Gmelin): a histochemical study. 45 38

A flow diagram for the automated determination of ferricyanide reductase activity in red blood cells was prepared in the modules from AutoAnalyzer AA I (Technicon Instruments Inc). Ferricyanide reductase assay can be substituted for assay of cytochrome b5 reductase (EC 1.6.2.2), which plays a major role in reducing methaemoglobin in erythrocytes, and is defective specifically in the erythrocytes of patients with hereditary methaemoglobinaemia. The effective sampling rate of the analysis is 30/h, and less than 0.05 ml of whole blood is required. Interference of haemoglobin with absorption by potassium ferricyanide at 420 nm is effectively exculded by dialysis. This automated method was compared with the accepted diaphorase method, and it distinguished clearly the ferricyanide reductase activity of cord bloods from that of adult bloods. The activity of the blood from a patient with hereditary methaemoglobinaemia was only residual. It is suggested that the method is useful as a mass screening test for hereditary methaemoglobinaemia.
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PMID:Automated determination of red cell methaemoglobin reductase activity by a continuous-flow system for screening hereditary methaemoglobinaemia. 46 15

Techniques for the ultrastructural demonstration of dehydrogenases in cerebral cortex are described. The best fixation for good fine structural preservation and retention of LDH and NADH-diphorase was obtained by perfusion with a misture of formaldehyde and glutaraldehyde and for SDH by perfusion with formaldehyde. Comparison of incubation conditions showed that consistent results were obtained using enzyme markers NBT and DS-NBT for LDH and NADH-diaphorase: DS-NBT was more satisfactory than NBT and BSPT for SDH. Penetration of incubation media was improved by Triton X-100: DMSO and ultrasonic treatment were less effective. The techniques enabled the first electron cytochemical demonstration of dehydrogenases in different elements of prefixed cerebral cortex. Ultrastructural sites of enzyme activities were localized within cristae and inter-membrane spaces of mitochondria in nerve cell cytoplasm and its processes, oligodendrocytes and astrocytes. Authenticity of the ultrastructural sites was confirmed by four different control experiments.
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PMID:Ultrastructural demonstration of dehydrogenases in rat cerebral cortex. 47 91


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