|Superclasses:||an amine → a quaternary amine|
Component of: BetI-choline
Summary from MetaCyc:
Choline is a quaternary ammonium compound and a fundamental metabolite for eukaryotic organisms, forming the head group of important phospholipids such as phosphatidylcholine [Mou02].
Choline is also the precursor for the neurotransmitter acetylcholine, and serves as a precursor for the formation of the important osmoprotectant glycine betaine (see glycine betaine biosynthesis III (plants) for an example) .
Animals cannot synthesize choline, which must be consumed through the diet, making it a vitamin. It is usually grouped within the B-complex vitamins.
Most microbes are also not able to produce choline, although many have transporters for its uptake.
Chemical Formula: C5H14NO
Molecular Weight: 104.17 Daltons
Monoisotopic Molecular Weight: 104.10753907670001 Daltons
Standard Gibbs Free Energy of Change Formation (ΔfG'° in kcal/mol): -49.21
Reactions known to consume the compound:
Reactions known to produce the compound:
In Reactions of unknown directionality:
Not in pathways:
BetI + choline = BetI-choline
In Transport reactions:
choline[periplasm] + H+[periplasm] → choline[cytosol] + H+[cytosol],
choline[cytosol] + 2 H+[periplasm] → choline[periplasm] + 2 H+[cytosol],
a quaternary amine[periplasm] + ATP + H2O → a quaternary amine[cytosol] + ADP + phosphate + H+
Enzymes inhibited by choline, sorted by the type of inhibition, are:Inhibitor (Competitive) of: betaine aldehyde dehydrogenase [Falkenberg90] Inhibitor (Mechanism unknown) of: L-proline:H+ symporter [MacMillan99], crotonobetainyl-CoA reductase [Roth94]
Falkenberg90: Falkenberg P, Strom AR (1990). "Purification and characterization of osmoregulatory betaine aldehyde dehydrogenase of Escherichia coli." Biochim Biophys Acta 1990;1034(3);253-9. PMID: 2194570
MacMillan99: MacMillan SV, Alexander DA, Culham DE, Kunte HJ, Marshall EV, Rochon D, Wood JM (1999). "The ion coupling and organic substrate specificities of osmoregulatory transporter ProP in Escherichia coli." Biochim Biophys Acta 1420(1-2);30-44. PMID: 10446288
Mou02: Mou Z, Wang X, Fu Z, Dai Y, Han C, Ouyang J, Bao F, Hu Y, Li J (2002). "Silencing of phosphoethanolamine N-methyltransferase results in temperature-sensitive male sterility and salt hypersensitivity in Arabidopsis." Plant Cell 14(9);2031-43. PMID: 12215503
Roth94: Roth S, Jung K, Jung H, Hommel RK, Kleber HP (1994). "Crotonobetaine reductase from Escherichia coli--a new inducible enzyme of anaerobic metabolization of L(-)-carnitine." Antonie Van Leeuwenhoek 1994;65(1);63-9. PMID: 8060125
©2015 SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025-3493