SMPDB_ID

SMP0000455

PW_ID

PW000027

图片

主题

Metabolic

描述

Homocysteine is an amino acid and homologue of cysteine that appears in the body as a result of the degradation of methionine. In mammals, homocysteine is used to biosynthesize cysteine via the following pathway. First the enzyme cystathionine beta-synthetase irreversibly condenses homocysteine with L-serine, forming L-cystathionine. The L-cystathionine is then cleaved by cystathionine gamma-lyase, producing 2-oxobutanoate, L-cysteine, and ammonia. The 2-oxobutanoate is further broken down via the 2-oxobutanoate degradation pathway, producing citric acid cycle intermediates, while the L-cysteine goes to the cysteine metabolism pathway. The homocysteine degradation pathway composes a part of the larger methionine metabolism pathway.

代谢物

SMPDB ID	代谢物id	代谢物的名字
SMP0000455	PW_C000035	Ammonia
SMP0000455	PW_C000448	L-Cysteine
SMP0000455	PW_C001148	Pyridoxal 5'-phosphate
SMP0000455	PW_C000067	L-Cystathionine
SMP0000455	PW_C001420	Water
SMP0000455	PW_C000120	L-Serine
SMP0000455	PW_C000590	Homocysteine
SMP0000455	PW_C000003	2-Ketobutyric acid

蛋白质

SMPDB ID	蛋白质id	蛋白质的名字
SMP0000455	P32929	Cystathionine gamma-lyase
SMP0000455	P35520	Cystathionine beta-synthase