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)

The effect of riboflavin deficiency on the activity of L-gulonolactone oxidase [L-gulono-gamma-lactone: oxygen 2-oxidoreductase, EC 1.1.3.8] and on vitamin C status was studied. A marked decrease in the specific activity of L-gulonolactone oxidase was observed in the liver microsomes isolated from riboflavin-deficient rats: the specific activity was approx. one-third of that in the microsomes isolated from control rats. The L-ascorbic acid content in the liver of the riboflavin-deficient rats was approx. one-half of that in the liver of the control rats. It seems that the rate of production of L-ascorbic acid in the riboflavin-deficient rats is limited by the decreased level of L-gulonolactone oxidase activity. Immunotitration using rabbit antiserum directed to L-gulonolactone oxidase revealed that a substantial amount of an inactive form of this enzyme is present in the liver microsomes of the riboflavin-deficient rats. L-Gulonolactone oxidase activity in the microsomes of these rats increased by approx. 35% upon addition of FAD, but it was slightly decreased by the addition of FMN or riboflavin. These results indicate that the liver microsomes of the riboflavin-deficient rats contain a protein which exhibits L-gulonolactone oxidase activity upon addition of Fad.
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PMID:L-gulonolactone oxidase activity and vitamin C status in riboflavin-deficient rats. 739 29

L-Gulono-gamma-lactone oxidase, an enzyme functioning in L-ascorbic acid biosynthesis in higher animals, possesses a covalently-bound FAD as the prosthetic group. Catalytically-active enzyme was expressed in silkworm cells by a recombinant baculovirus encoding rat L-gulono-gamma-lactone oxidase. When recombinant enzyme was expressed under riboflavin-deficient conditions, most of it was found to be the apoprotein, as evidenced by an increase in enzymic activity upon addition of FAD to the assay mixture. Interestingly, the observed enzymic activity is thought to have been provoked by a noncovalent interaction between FAD and the apoprotein, since the covalent attachment of FAD was not demonstrated by a fluorometric gel-scanning experiment.
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PMID:Production by a baculovirus expression system of the APO-protein of L-gulono-gamma-lactone oxidase, a flavoenzyme possessing a covalently-bound FAD. 795 Oct 49

A gene encoding a novel intracellular sorbitol oxidase of a soil bacterium, Streptomyces sp. H-7775, was cloned and sequenced. The gene consists of an open reading frame of 1,260-bp encoding a protein of 420 amino acids with a molecular weight of 45,148. Deduced amino acid sequence of the gene has 25.3% identity and 68.1% similarity to that of rat L-gulonolactone oxidase at the overall amino acids. Nucleotide-binding motifs were not found in the deduced amino acid sequence of SOX protein. We succeeded in expressing recombinant sorbitol oxidase with covalently bound FAD in E. coli at about a 4,000-fold higher total enzyme activity than that of the Streptomyces sp. H-7775. The enzymatic properties of the recombinant SOX were similar to those of the enzyme from Streptomyces sp. H-7775. This is the first report of the cloning and expression of a newly categorized enzyme, sorbitol oxidase, from Streptomyces sp.
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PMID:Molecular cloning and expression of a gene encoding a novel sorbitol oxidase from Streptomyces sp. H-7775. 953 93

A thermophilic bacterium, Streptomyces sp. IKD472, that can oxidize xylitol was isolated from a hot spring and was found to produce xylitol oxidase. The purified enzyme was a monomeric protein with an apparent molecular weight of 43 k as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel filtration. This novel enzyme is capable of catalyzing the oxidation of one mole of xylitol to form one mole each of xylose and hydrogen peroxide. Since the V(max)K(m) value for xylitol was two and four times higher than those for galactitol and n-sorbitol, respectively, the enzyme was designated as xylitol oxidase. The enzyme was stable in the pH range from 5.5 to 10.5 and at temperatures up to 65 degrees C. The optimal temperature and pH were 55 degrees C and pH 7.5, respectively. Xylitol oxidase bound one mole of FAD as a coenzyme per mole of protein. The amino acid sequence of the NH2 terminus and the fragments obtained by lysylendpeptidase digestion of xylitol oxidase were determined for preparation of synthetic oligonucleotides as hybridization probes. A 2.8-kb chromosomal fragment hybridizing to the probes was cloned into pUC18 in Escherichia coli. The gene consists of an open reading frame of 1245 by that encodes a protein containing 415 amino acids with a molecular weight of 44,730 but without the conserved nucleotide-binding sequence, Gly-X-Gly-X-X-Gly. The amino acid sequence has 70% identity to putative oxidoreductase from Streptomyces coelicolar, 51% to sorbitol oxidase from Streptomyces sp., and 26% to L-gulonolactone oxidase from rat in terms of the overall amino acid sequence. DNA manipulation of the cloned gene in E. coli, by alteration of a strong promoter and a synthesized ribosome-binding sequence at an appropriate position, resulted in overproduction of xylitol oxidase 100 times more than that produced in the original Streptomyces sp. IKD472. The enzyme properties of recombinant xylitol oxidase were the same as those of the authentic enzyme. Stable xylitol oxidases, which allow easier quantitative analysis of xylitol, are useful for clinical applications.
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PMID:Isolation, characterization, and molecular cloning of a thermostable xylitol oxidase from Streptomyces sp. IKD472. 1623 58