User:Justme26/L-gulonolactone oxidase

Lead
 L -Gulonolactone oxidase (EC 1.1.3.8) is an enzyme that produces vitamin C. Its expressed in mice and rats, but is non-functional in Haplorrhini (a suborder of primates, including humans), in some bats, and in guinea pigs. It catalyzes the reaction of L -gulono-1,4-lactone with oxygen to form L -xylo-hex-3-gulonolactone (2-keto-gulono-γ-lactone) and hydrogen peroxide. It uses FAD as a cofactor. The L -xylo-hex-3-gulonolactone then converts to ascorbic acid spontaneously, without enzymatic action.The structure of L-gulonolactone oxidase in rats helps identify characteristics of this enzyme.

L-gulonolactone oxidase in Rats
L-gulonolactone oxidase (GULO) is an enzyme that helps catalyze the production of ascorbic acid aka vitamin C. Mammals such as humans and guinea pigs do not express this gene due to multiple mutations in a specific exon. These mutations correlate to nucleotide substitution. Rats are a species that do express L-gulonolactone oxidase with a specific gene transcript. The protein coding region of the gene 645 base-pairs long, with eight exons and seven introns. The amino acid sequence of this protein has suggested that rat L-Gulonolactone oxidase is located in the membrane portion of the endoplasmic reticulum due to its multiple B-sheet structure which contains hydrophobic areas. It has been determined that rat GULO has a prosthetic domain in the N-terminus, flavian adenine dinucleotide. The only substrates that can make this rat enzyme function are L-GalL and L-GulL.

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