ID   1.4.1.27
DE   glycine cleavage system.
AN   GCV.
CA   (6S)-5,6,7,8-tetrahydrofolate + glycine + NAD(+) = (6R)-5,10-methylene-
CA   5,6,7,8-tetrahydrofolate + CO2 + NADH + NH4(+).
CC   -!- The glycine cleavage (GCV) system is a large multienzyme complex that
CC       belongs to the 2-oxoacid dehydrogenase complex family, which also
CC       includes EC 1.2.1.25, EC 1.2.1.105, EC 1.2.1.104 and EC 2.3.1.190.
CC   -!- The GCV system catalyzes the reversible oxidation of glycine,
CC       yielding carbon dioxide, ammonia, 5,10-methylenetetrahydrofolate and
CC       a reduced pyridine nucleotide.
CC   -!- Tetrahydrofolate serves as a recipient for one-carbon units generated
CC       during glycine cleavage to form the methylene group.
CC   -!- The GCV system consists of four protein components, the P protein
CC       (EC 1.4.4.2), T protein (EC 2.1.2.10), L protein (EC 1.8.1.4),
CC       and the non-enzyme H protein (lipoyl-carrier protein).
CC   -!- The P protein catalyzes the pyridoxal phosphate-dependent liberation
CC       of CO2 from glycine, leaving a methylamine moiety.
CC   -!- The methylamine moiety is transferred to the lipoic acid group of the
CC       H protein, which is bound to the P protein prior to decarboxylation
CC       of glycine.
CC   -!- The T protein catalyzes the release of ammonia from the methylamine
CC       group and transfers the remaining C1 unit to tetrahydrofolate,
CC       forming 5,10-methylenetetrahydrofolate.
CC   -!- The L protein then oxidizes the lipoic acid component of the H
CC       protein and transfers the electrons to NAD(+), forming NADH.
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