Figure 4
From: Dysfunction in the coagulation system and schizophrenia
Homocysteine may be recycled to methionine or eliminated in urine as sulfate. Under conditions in which excess methionine is present, homocysteine condenses with serine to form cystathionine in a reaction catalyzed by the vitamin B6–dependent rate-limiting enzyme cystathionine β synthase. B12, vitamin B12; B6, vitamin B6; CβS, cystathionine β-synthase; MTHFR, methylene-tetrahydrofolate reductase; THF, tetrahydrofolate. Adapted from ref. 66.
