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)

We isolated cDNA (pgCYR, about 2.1 kb) and genomic DNA (pgGYR, about 4 kb) clones coding for NADPH-cytochrome P450 reductase by immunoscreening of yeast Saccharomyces cerevisiae cDNA and genomic DNA libraries in phage lambda gt11. The clones were sequenced and found to encode a protein of 691 amino acid residues with a calculated molecular weight of 76,737 daltons. The amino-terminal sequence (excluding the initial methionine residue) deduced therefrom was in agreement with the protein sequence of the yeast reductase. In addition, the deduced sequence included the partial amino acid sequence determined with the papain-solubilized reductase. The total amino acid sequence of the yeast reductase showed 33-34% similarity with those of the rat, rabbit, pig, and trout reductases. In spite of low similarity in the total amino acid sequences, the possible functional domains related to binding of FAD, FMN, and NADPH were well conserved among all five species compared.
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PMID:Primary structure of Saccharomyces cerevisiae NADPH-cytochrome P450 reductase deduced from nucleotide sequence of its cloned gene. 313 48

Two-electron reduced glutathione reductase from yeast reacted with iodoacetamide is alkylated almost exclusively in the nascent thiol nearer the amino terminus of the protein. The charge-transfer absorbance, maximal at 530 nm, characteristic of the two-electron reduced enzyme is not lost as the alkylation proceeds, and the product has a spectrum virtually identical with that of the two-electron reduced enzyme. This observation demonstrates that the thiol alkylated is not the charge-transfer-donor thiolate which interacts with the FAD. The spectrum of the monoalkylated derivative is stable in the presence of oxidized glutathione, indicating that the charge-transfer-donor thiol is not involved in interchange with the substrate in the native enzyme. Thus, the nascent thiols produced upon two-electron reduction of glutathione reductase have distinct functions, interchange with the substrate and interaction with the FAD. Treatment of the monoalkylated derivative with the apolar phenylmercuric acetate eliminates the charge-transfer interaction. The spectrum of the resulting species is similar to that of the oxidized enzyme but less resolved and blue shifted by 10 nm. The dependence on pH of the absorbance associated with the thiolate to FAD charge-transfer interaction in native two-electron reduced glutathione reductase is biphasic, with pK values at approximately 4.8 and 7.4. By analogy with glyceraldehyde-3-phosphate dehydrogenase and papain, these data indicate that the thiolate is stabilized by an adjacent basic residue. The pK 7.4 is associated with the titration of the base to give the ion pair, and the pK of 4.8 is associated with the titration of the thiolate. Unlike lipoamide dehydrogenase, glutathione reductase is sufficiently stable to allow titration with dithionite at pH 3.7. The spectrum at this pH is essentially the same as that of the monoalkylated derivative treated with phenylmercuric acetate. The changes with pH are completely reversible.
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PMID:Glutathione reductase from yeast. Differential reactivity of the nascent thiols in two-electron reduced enzyme and properties of a monoalkylated derivative. 701 96

Sulfenic acids (R-SOH) result from the stoichiometric oxidations of thiols with mild oxidants such as H2O2; in solution, however, these derivatives accumulate only transiently due to rapid self-condensation reactions, further oxidations to the sulfinic and/or sulfonic acids, and reactions with nucleophiles such as R-SH. In contrast, oxidations of cysteinyl side chains in proteins, where disulfide bond formation can be prevented and where the reactivity of the nascent cysteine-sulfenic acid (Cys-SOH) can be controlled, have previously been shown to yield stable active-site Cys-SOH derivatives of papain and glyceraldehyde-3-phosphate dehydrogenase. More recently, however, functional Cys-SOH residues have been identified in the native oxidized forms of the FAD-containing NADH peroxidase and NADH oxidase from Streptococcus faecalis; these two proteins constitute a new class within the flavoprotein disulfide reductase family. In addition, Cys-SOH derivatives have been suggested to play important roles in redox regulation of the DNA-binding activities of transcription factors such as Fos and Jun, OxyR, and bovine papillomavirus type 1 E2 protein. Structural inferences for the stabilization of protein-sulfenic acids, drawn from the refined 2.16-A structure of the streptococcal NADH peroxidase, provide a molecular basis for understanding the proposed redox functions of these novel cofactors in both enzyme catalysis and transcriptional regulation.
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PMID:Protein-sulfenic acid stabilization and function in enzyme catalysis and gene regulation. 826 33

Limited proteolysis of cellobiose dehydrogenase (CDH) from the white rot fungus Phanerochaete chrysosporium by papain cleaves the enzyme into two fragments containing flavin (FAD) and heme, respectively. Small-angle X-ray scattering (SAXS) was employed to investigate size and shape of intact CDH and of its fragments in solution. The largest dimension of CDH amounts to about 18 nm, whereas the corresponding quantity of each of the two fragments is only around 9 nm. CDH as well as its fragments appear to be of prolate shape, the cross-section of the FAD fragment (diameter 4.3 to 5.1 nm) being considerably larger than that of the heme fragment (diameter 3.3 nm). These findings suggest a collinear arrangement of the two domains in the CDH particle. Simulations based on the method of finite elements corroborate this structure model and furthermore suggest the existence of a possibly flexible linker between the two domains.
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PMID:Small-angle X-ray scattering studies on cellobiose dehydrogenase from Phanerochaete chrysosporium. 865 22