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Aldehyde dehydrogenase, dimeric NADP-preferring is an enzyme that in humans is encoded by the ''ALDH3A1'' gene.〔(【引用サイトリンク】 url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=218 )〕 Aldehyde dehydrogenases oxidize various aldehydes to the corresponding acids. They are involved in the detoxification of alcohol-derived acetaldehyde and in the metabolism of corticosteroids, biogenic amines, neurotransmitters, and lipid peroxidation. The enzyme encoded by this gene forms a cytoplasmic homodimer that preferentially oxidizes aromatic aldehyde substrates. The gene is located within the Smith-Magenis syndrome region on chromosome 17.〔 ALDH3A1 expression is notably high in the cornea of mammalian species, comprising from 5 to 50% of soluble protein content, but is almost absent from the cornea of other vertebrates. == Structure and mechanism == ALDH3A1 is a homodimer consisting of alpha helices (43.8%), beta sheets (4.2%), p-loop turns (28.2%) and random coils (23.8%). The catalytic residue–Cys244—is located on an active site that contains a Rossman fold that binds the enzyme's cofactor, NAD(P)+. ALDH3A1’s catalytic mechanism mirrors that of other enzymes of the aldehyde dehydrogenase family. The sulfur atom of Cys244 attacks the carbonyl of the aldehyde substrate in a nucleophilic attack that releases a hydride ion. The hydride ion is accepted by the NAD(P)+ bound to the Rossman fold. Unique interactions between the cofactor and the Rossman fold facilitate an isomerization of the enzyme that releases the cofactor while maintaining the integrity of the active site. A water molecule enters the active site and is subsequently activated by a glutamate residue. The activated water then attacks the thioester enzyme-substrate complex in nucleophilic reaction that regenerates the free enzyme, and releases the corresponding carboxylic acid. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Aldehyde dehydrogenase 3 family, member A1」の詳細全文を読む スポンサード リンク
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