|Superclasses:||Reactions Classified By Conversion Type → Simple Reactions → Chemical Reactions|
|Reactions Classified By Substrate → Small-Molecule Reactions|
EC Number: 220.127.116.11
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.
Mass balance status: Balanced.
Enzyme Commission Primary Name: choline dehydrogenase
Enzyme Commission Synonyms: choline oxidase, choline-cytochrome c reductase, choline:(acceptor) oxidoreductase, choline:(acceptor) 1-oxidoreductase
This is the first reaction in the betaine biosynthetic pathway.
Enzyme Commission Summary:
A quinoprotein. In many bacteria, plants and animals, the osmoprotectant betaine is synthesized using different enzymes to catalyse the conversion of (1) choline into betaine aldehyde and (2) betaine aldehyde into betaine. In plants, the first reaction is catalysed by EC 18.104.22.168, choline monooxygenase, whereas in animals and many bacteria, it is catalysed by either membrane-bound choline dehydrogenase (EC 22.214.171.124) or soluble choline oxidase (EC 126.96.36.199) [Waditee03]. The enzyme involved in the second step, EC 188.8.131.52, betaine-aldehyde dehydrogenase, appears to be the same in plants, animals and bacteria.
Gadda03: Gadda G, McAllister-Wilkins EE (2003). "Cloning, expression, and purification of choline dehydrogenase from the moderate halophile Halomonas elongata." Appl Environ Microbiol 69(4);2126-32. PMID: 12676692
Waditee03: Waditee R, Tanaka Y, Aoki K, Hibino T, Jikuya H, Takano J, Takabe T (2003). "Isolation and functional characterization of N-methyltransferases that catalyze betaine synthesis from glycine in a halotolerant photosynthetic organism Aphanothece halophytica." J Biol Chem 278(7);4932-42. PMID: 12466265
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