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Last Updated: 2023-10-25
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.
Homocysteine Degradation References
Zimin AV, Delcher AL, Florea L, Kelley DR, Schatz MC, Puiu D, Hanrahan F, Pertea G, Van Tassell CP, Sonstegard TS, Marcais G, Roberts M, Subramanian P, Yorke JA, Salzberg SL: A whole-genome assembly of the domestic cow, Bos taurus. Genome Biol. 2009;10(4):R42. doi: 10.1186/gb-2009-10-4-r42. Epub 2009 Apr 24.Pubmed: 19393038
Harhay GP, Sonstegard TS, Keele JW, Heaton MP, Clawson ML, Snelling WM, Wiedmann RT, Van Tassell CP, Smith TP: Characterization of 954 bovine full-CDS cDNA sequences. BMC Genomics. 2005 Nov 23;6:166. doi: 10.1186/1471-2164-6-166.Pubmed: 16305752
This pathway was propagated using PathWhiz - Pon, A. et al. Pathways with PathWhiz (2015) Nucleic Acids Res. 43(Web Server issue): W552–W559.
Propagated from SMP0000455
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