Cystathionine beta-synthase (CBS)
Cofactors used
Clinical / pharmacological. Homocystinuria: marfanoid habitus, DOWNWARD lens dislocation, thrombosis; B6-responsive forms
What it does, reaction by reaction
Methionine Cycle / Transmethylation (SAM Cycle, homocysteine) Amino Acid & Nitrogen Metabolism · Cytosol
Homocysteine + L-serine → cystathionine + H₂O
Converts Homocysteine Serine into Cystathionine H2O
› Notes
Cystathionine β-synthase (CBS) uses PLP (vitamin B6) and a heme regulatory domain to catalyze the first transsulfuration step. It is the committed, essentially irreversible, rate-controlling step of transsulfuration and is activated by SAM when methionine/SAM abundance is high.
Showing all 1 reactions.
What accelerates and inhibits it
Regulation is pathway-specific, so each context is listed separately
No regulation recorded for this enzyme in the source documents.
Recent literature
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