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Pathway Description
Methionine Biosynthesis
Escherichia coli (strain K12)
Category:
Metabolite Pathway
Sub-Category:
Metabolic
Created: 2024-12-20
Last Updated: 2025-08-10
This pathway shows the biosynthesis of methionine, which is an energy-costly process. Lysine biosynthesis produces L-Aspartate-semialdehyde, which later on is catalyzed to L-homoserine by bifunctional aspartokinase (also named homoserine dehydrogenase) 1 and 2. Homoserine is then activated by O-succinylation to form O-succinyl-L-homoserine via homoserine O-succinyltransferase (metA). Combining with L-cysteine, O-succinyl-L-homoserine form L-cystathionine and succinic acid by cystathionine gamma-synthase (metB). Cleavage of L-cystathionine by cystathionine beta-lyase (metC) or Protein MalY(as ) generates two small molecules: homocysteine and 2-aminoprop-2-enoate. Methionine synthase(MetH) or 5-methyltetrahydropteroyltriglutamate--homocysteine methyltransferase(MetE) will catalyzehomocysteine to form the final product: methionine. In E.coli, MetH can only function with existence of cobalamin (Vitamin B12), which can be available in the guy; without cobalamin, MetE will not be repressed so that it will catalyze the methionine. Methionine can be transported out of cell (into periplasmic space) by leucine efflux transporter.
References
Methionine Biosynthesis References
Walt A, Kahn ML: The fixA and fixB genes are necessary for anaerobic carnitine reduction in Escherichia coli. J Bacteriol. 2002 Jul;184(14):4044-7. doi: 10.1128/jb.184.14.4044-4047.2002.
Pubmed: 12081978
Eichler K, Buchet A, Bourgis F, Kleber HP, Mandrand-Berthelot MA: The fix Escherichia coli region contains four genes related to carnitine metabolism. J Basic Microbiol. 1995;35(4):217-27.
Pubmed: 7473063
Yura T, Mori H, Nagai H, Nagata T, Ishihama A, Fujita N, Isono K, Mizobuchi K, Nakata A: Systematic sequencing of the Escherichia coli genome: analysis of the 0-2.4 min region. Nucleic Acids Res. 1992 Jul 11;20(13):3305-8. doi: 10.1093/nar/20.13.3305.
Pubmed: 1630901
Oshima T, Aiba H, Baba T, Fujita K, Hayashi K, Honjo A, Ikemoto K, Inada T, Itoh T, Kajihara M, Kanai K, Kashimoto K, Kimura S, Kitagawa M, Makino K, Masuda S, Miki T, Mizobuchi K, Mori H, Motomura K, Nakamura Y, Nashimoto H, Nishio Y, Saito N, Horiuchi T, et al.: A 718-kb DNA sequence of the Escherichia coli K-12 genome corresponding to the 12.7-28.0 min region on the linkage map. DNA Res. 1996 Jun 30;3(3):137-55. doi: 10.1093/dnares/3.3.137.
Pubmed: 8905232
Blattner FR, Plunkett G 3rd, Bloch CA, Perna NT, Burland V, Riley M, Collado-Vides J, Glasner JD, Rode CK, Mayhew GF, Gregor J, Davis NW, Kirkpatrick HA, Goeden MA, Rose DJ, Mau B, Shao Y: The complete genome sequence of Escherichia coli K-12. Science. 1997 Sep 5;277(5331):1453-62. doi: 10.1126/science.277.5331.1453.
Pubmed: 9278503
Hayashi K, Morooka N, Yamamoto Y, Fujita K, Isono K, Choi S, Ohtsubo E, Baba T, Wanner BL, Mori H, Horiuchi T: Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 and W3110. Mol Syst Biol. 2006;2:2006.0007. doi: 10.1038/msb4100049. Epub 2006 Feb 21.
Pubmed: 16738553
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 SMP0000834
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