Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D02011 (FAD)
 5,530 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Delta5-3beta-hydroxysteroid oxidoreductase was extracted in magnesium-containing Tris buffer from sonicated Streptomyces griseocarneus cells. The enzyme was partially purified (150 X) by ion exchange chromatography and gel filtration following (NH4)2SO4 fractionation. Upon gel filtration on Sephadex G-75 to G-200, the greatest part of the activity gave a peak in the fractionation range. The enzyme obtained from the gel yielded small enzyme molecules on repeated chromatography. A molecular weight of 32 to 36 000 was calculated for the activity appearing in the fractionation range of Sephadex G-75 to G-200. The enzyme is highly specific for the irreversible oxidation of the 3beta-hydroxyl group in steroids with a trans-anellated A : B ring system with either C5 or C6 double bond. Delta5-3-ketosteroids are converted into delta5-3-ketosteroids at a high rate, but the isomerase activity cannot be separated from the oxidoreductase activity either by chromatography or by selective heat inactivation. NAD, NADP, FMN or FAD did not influence the activity, but the enzyme is inactive in the absence of molecular oxygen.
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PMID:Properties of delta5-3beta-hydroxysteroid oxidoreductase isolated from Streptomyces griseocarneus. 0 56

1. Alcohol oxidase (alcohol: oxygen oxidoreductase) of a thermophilic methanol-utilizing yeast, Hansenula polymorpha DL-1, was isolated in crystalline form. 2. This alcohol oxidase of H. polymorpha was more stable to heat than was the enzyme of Kloeckera sp. This difference in heat stability is compatible with the difference in growth temperatures for both yeasts. 3. The crystalline alcohol oxidases of both yeast oxidized the lower primary alcohols (C-2 to C-4) as well as methanol. The apparent Km values for the methanol of Kloeckera and H. polymorpha enzymes were 0.44 and 0.23 mM, respectively. The enzymes could also oxidize formaldehyde to formate, and were inactivated by relatively low concentrations of hydrogen peroxide. 4. The molecular weight for both enzymes was calculated to be about 670000. Each enzyme is composed of eight identical subunits (molecular weight 83000) and contains eight moles of FAD as the prosthetic group. The NH2-terminal and COOH-terminal amino acids of H. polymorpha enzyme were identified as alanine and phenylalanine, respectively. The octameric subunits model of each enzyme was confirmed by electron micrographs, which showed an octad aggregate, composed of two tetragons face to face.
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PMID:Alcohol oxidases of Kloeckera sp. and Hansenula polymorpha. Catalytic properties and subunit structures. 0 73

2-Nitropropane dioxygenase, purified to homogeneity from Hansenula mrakii (IFO 0895), has a molecular weight of approximately 62,000 and consists of two subunits nonidentical in molecular weight (39,000 and 25,000). Stoichiometrical studies and the results obtained with 18O2 showed that 2 atoms of molecular oxygen are incorporated into 2 molecules of acetone formed from 2-nitropropane. In addition to 2-nitropropane, nitroethane, 3-nitro-2-pentanol, and 1-nitropropane are oxidatively dentrified. The enzyme, which exhibits absorption maxima at 274, 370, 415, and 440 nm and a shoulder at 470 nm, contains 1 mol of FAD and 1 g atom of non-heme iron per mol of enzyme. The enzyme-bound FAD is reduced by 2-nitropropane under anaerogic conditions, but the enzyme-bound Fe3+ is not affected. The introduction of oxygen to the reduced form of enzyme causes reoxidation of the enzyme. The bound FAD and Fe3+ are reduced by the addition of nitromethane, which is not a substrate, under anaerobic conditions. The aerobic dialysis of the enzyme treated with nitromethane causes reoxidation of only the Fe2+. Sodium dithionite also reduces both the enzyme-bound FAD and Fe3+ under anaerobic conditions. When the enzyme is dialyzed against 10 mM potassium phosphate buffer (pH 7.0) immediately after reduction by dithionite, the absorption spectrum similar to that of the native enzyme appeared with concomitant restoration of approximately 80% of the activity. The enzyme activity is significantly inhibited by pyrocatechol-3,5-disulfonate disodium salt, 8-hydroxyquinoline, reducing agents such as 2-mercaptoethanol, and HgCl2. The Michaelis constants are as follows: 2-nitropropane (2.13 X 10(-2) M), nitroethane (2.43 X 10(-2) M), 3-nitro-2-pentanol (6.8 X 10(-3) M), 1-nitropropane (2.56 X 10(-2) M), and oxygen (3.03 X 10(-4) M, with 2-nitropropane).
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PMID:A new oxygenase, 2-nitropropane dioxygenase of Hansenula mrakii. Enzymologic and spectrophotometric properties. 1 Dec 14

1. The effects of various inhibitors and activators on the azo- and nitro-reductases of Moniezia expansa have been studied. Both reductions were partially inhibited by FAD, FMN, riboflavin, allopurinol, dicoumarol, 5-nitro-2-furaldehyde, azide and cyanide at 1 mM. Both reactions were stimulated by hypoxanthine. Menadione, nitrofurantoin, SKF 525-A (2-diethylaminoethyl 2,2-diphenylvalerate) and fluoride were without effect. 2. Xanthine- and aldehyde-oxidase activities were not detected in the enzyme preparation. 3. The substrate specificity of the azo- and nitro-reductases were determined. Azobenzene, 4-dimethylamino-azobenzene and 1,2-dimethyl-4-(4-carboxyphenylazo)-5-hydroxybenzene, nitrobenzene, 4-nitrohippuric acid and the isomers of nitrophenol, nitroanisole, nitrobenzoic acid, nitrobenzaldehyde and nitrobenzyl alcohol were reduced. Nitrobenzaldehyde isomers were not reduced to the alcohols and the coumaric acids were not reduced to the phenylpropionic acids. 4. The products of azo- and nitro-reduction were the corresponding amines; hydroxylamino- and hydrazo-compounds were not detected. 5. The pH optima and cofactor requirements were the same for both azo- and nitro-reduction. Neither reaction was inhibited by oxygen.
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PMID:Azo- and nitro-reductases of the cestode Moniezia expansa. Substrate specificity, reaction products and the effects of flavins and other compounds. 1 14

A flavoprotein catalyzing the reduction of cytochrome c by NADPH was solubilized and purified from microsomes of yeast grown anaerobically. The cytochrome c reductase had an apparent molecular weight of 70,000 daltons and contained one mole each of FAD and FMN per mole of enzyme. The reductase could reduce some redox dyes as well as cytochrome c, but could not catalyze the reduction of cytochrome b5. The reductase preparation also catalyzed the oxidation of NADPH with molecular oxygen in the presence of a catalytic amount of 2-methyl-1,4-naphthoquinone (menadione). The Michaelis constants of the reductase for NADPH and cytochrome c were determined to be 32.4 and 3.4 micron M, respectively, and the optimal pH for cytochrome c reduction was 7.8 to 8.0. It was concluded that yeast NADPH-cytochrome c reductase is in many respects similar to the liver microsomal reductase which acts as an NADPH-cytochrome P-450 reductase [EC 1.6.2.4].
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PMID:Studies on the microsomal electron-transport system of anaerobically grown yeast. V. Purification and characterization of NADPH-cytochrome c reductase. 1 31

Cyclohexylamine oxidase was purified 90-fold from cell-free extracts of Pseudomonas sp. capable of assimilating sodium cyclamate. The purified enzyme was homogeneous in disc electrophoresis, and the molecular weight was found to be approximately 80,000 by gel filtration. The enzyme catalyzed the following reaction: cyclohexylamine+O2+H2O leads to cyclohexanone+NH3+H2O2. The enzyme thus can be classified as an amine oxidase; it utilized oxygen as the ultimate electron acceptor. The pH optimum of the reaction was 6.8 and the apparent Km value for cyclohexylamine was 2.5 X 10(-4) M. The enzyme was highly specific for the deamination of alicyclic primary amines such as cyclohexylamine, but was found to be inactive toward ordinary amines used as substrates for amine oxidases. The enzyme solution was yellow in color and showed a typical flavoprotein spectrum; the addition of cyclohexylamine under anaerobic conditions caused reduction of the flavin in the native enzyme. The flavin of the prosthetic group was identified as FAD by thin layer chromatography. The participation of sulfhydryl groups in the enzymic action was also suggested by the observation that the enzyme activity was inhibited in the presence of PCMB and could be recovered by the addition of glutathione.
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PMID:Purification and some properties of cyclohexylamine oxidase from a Pseudomonas sp. 1 51

Yeast microbodies containing FAD-dependent alcohol oxidase, catalase and D-amino acid oxidase were isolated from methanol-grown cells of Kloeckera sp. 2201 and immobilized intact in matrices formed by a short-time illumination of photo-crosslinkable resin oligomers. The relative activities of catalase, alcohol oxidase and D-amino acid oxidase of the gel-entrapped microbodies were 36, 76 and 31% respectively as compared with those of free microbodies. Immobilization enhance d the stability of catalase to a certain degree, but not that of alcohol oxidase. The pH/activity profiles of catalase and alcohol oxidase of the entrapped organelles showed more narrow pH optima than those of the free counterparts. D-Amino acid oxidase in immobilized microbodies showed a somewhat higher Km value for D-alanine than that in free ones. Immobilized microbodies oxidized two moles of methanol to form two moles of formaldehyde with consumption of one mole of molecular oxygen. Addition of 3-amino-1,2,4-triazole, an inhibitor of catalase, reduced the formation of formaldehyde to half the amount without change in the amount of oxygen consumed, indicating the synergic action of alcohol oxidase and catalase in methanol oxidation in the microbodies of living yeast cells.
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PMID:Immobilization of yeast microbodies by inclusion with photo-crosslinkable resins. 2 91

Hepatic microsomal NADPH-cytochrome P-450 reductase was solubilized from rabbit liver microsomes in the presence of detergents and purified to homogeneity by column chromatography. The purified reductase had a molecular weight of 78 000 and contained 1 mol each of FAD and FMN per mol of enzyme. On reduction with NADPH in the presence of molecular oxygen, an 02-stable semiquinone containing one flavin free radical per two flavins was formed, in agreement with previous work on purified trypsin-solubilized reductase. The reduction of oxidized enzyme by NADPH, and autoxidation of NADPH-reduced enzyme by air, proceeded by both one-electron equivalent and two-electron equivalent mechanisms. The reductase reduced cytochrome P-450 (from phenobarbital-treated rabbits) and cytochrome P-448 (from 3-methylcholanthrene-treated rabbits). The rate of reduction of cytochrome P-450 increased in the presence of a substrate, benzphetamine, but that of cytochrome P-448 did not.
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PMID:Studies on the microsomal mixed function oxidase system: redox properties of detergent-solubilized NADPH-cytochrome P-450 reductase. 2 10

The exchange of bound FAD for free FAD was studied with D-amino acid oxidase (D-amino acid:oxygen oxidoreductase (deaminating), EC 1.4.3.3) and beta-D-glucose oxidase (beta-D-glucose:oxygen 1-oxidoreductase, EC 1.1.3.4). For a simple measurement of the reaction rate, equimolar amounts of the enzyme and [14C]FAD were mixed. The exchange occurred very rapidly in the holoenzyme of D-amino acid oxidase at 25 degrees C, pH 8.3 (half life of the exchange: 0.8 min), but slowly in the presence of the substrate or a competitive inhibitor, benzoate. It also occurred slowly in the purple complex of D-amino acid oxidase. In the case of beta-D-glucose oxidase, however, the exchange occurred very slowly at 25 degrees C, pH 5.6, regardless of the presence of the substrate or p-chloromercuribenzoate. On the basis of these findings, the turnover of the coenzymes of flavin enzymes in mammals is discussed.
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PMID:Exchange of free and bound coenzyme of flavin enzymes studied with [14C]FAD. 3 12

We have shown that the isolated sarcoplasmic reticulum from rabbit slow muscle contains cytochrome b5 which can be reduced via a flavoprotein, with FAD as the prosthetic group. In the presence of NADH and oxygen, these sarcoplasmic reticulum membranes can convert stearyl-CoA to oleyl-CoA, similarly to liver endoplasmic reticulum membranes. However, the stearyl-CoA desaturase system is virtually lacking in fast muscle sarcoplasmic reticulum. The data suggest that these differences between fast and slow twitch muscle may be related to the characteristic fatty acid composition of phospholipids and the function of the sarcoplasmic reticulum.
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PMID:Evidence for the presence of the stearyl-CoA desaturase system in the sarcoplasmic reticulum of rabbit slow muscle. 3 16


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