# RequirementNotMet

orgId: NCBI__GCA_016873795.1
pathwayId: cys
ruleId: from-serine-homocysteine
requiredPathwayId: met
requiredRuleId: homocysteine
comment:
Cysteine biosynthesis via the reverse transsulfuration pathway requires homocysteine, which is an intermediate in methionine biosynthesis. Homocysteine is also an intermediate in the S-adenosylmethionine cycle, so many organisms that cannot synthesize methionine can convert it to homocysteine.


