Choline monooxygenase

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In enzymology, a choline monooxygenase (EC 1.14.15.7) is an enzyme that catalyzes the chemical reaction

choline + O₂ + 2 reduced ferredoxin + 2 H⁺ $\rightleftharpoons$ betaine aldehyde hydrate + H₂O + 2 oxidized ferredoxin

The 4 substrates of this enzyme are choline, O₂, reduced ferredoxin, and H⁺, whereas its 3 products are betaine aldehyde hydrate, H₂O, and oxidized ferredoxin.

This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with reduced iron-sulfur protein as one donor, and incorporation o one atom of oxygen into the other donor. The systematic name of this enzyme class is choline,reduced-ferredoxin:oxygen oxidoreductase. This enzyme participates in glycine, serine and threonine metabolism.

[edit] References

IUBMB entry for 1.14.15.7
BRENDA references for 1.14.15.7 (Recommended.)
PubMed references for 1.14.15.7
PubMed Central references for 1.14.15.7
Google Scholar references for 1.14.15.7
Brouquisse R, Weigel P, Rhodes D, Yocum CF and Hanson AD (1989). "Evidence for a ferredoxin-dependent choline monooxygenase from spinach chloroplast stroma". Plant Physiol. 90: 322–329.
Burnet M, Lafontaine PJ, Hanson AD (1995). "Assay, Purification, and Partial Characterization of Choline Monooxygenase from Spinach". Plant. Physiol. 108: 581–588. PMID 12228495.
Scott P, Golbeck JH, Hanson AD (1997). "Choline monooxygenase, an unusual iron-sulfur enzyme catalyzing the first step of glycine betaine synthesis in plants: prosthetic group characterization and cDNA cloning". Proc. Natl. Acad. Sci. U. S. A. 94: 3454–8. doi:10.1073/pnas.94.7.3454. PMID 9096415.
Russell BL, Rathinasabapathi B, Hanson AD (1998). "Osmotic stress induces expression of choline monooxygenase in sugar beet and amaranth". Plant. Physiol. 116: 859–65. doi:10.1104/pp.116.2.859. PMID 9489025.
Gage DA and Hanson AD (1998). "Glycine betaine synthesis in transgenic tobacco expressing choline monooxygenase is limited by the endogenous choline supply". Plant J. 16: 101–110.
AD (1998). "The endogenous choline supply limits glycine betaine synthesis in transgenic tobacco expressing choline monooxygenase". Plant. J. 16: 487–96. doi:10.1046/j.1365-313x.1998.00316.x. PMID 9881168.
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: 4932–42. doi:10.1074/jbc.M210970200. PMID 12466265.