Cystathionine beta-Synthase

**Definition:** A multifunctional pyridoxal phosphate enzyme. In the second stage of cysteine biosynthesis it catalyzes the reaction of homocysteine with serine to form cystathionine with the elimination of water. Deficiency of this enzyme leads to HYPERHOMOCYSTEINEMIA and HOMOCYSTINURIA. EC 4.2.1.22.

**Tree numbers:** - D08.811.520.241.300.200

**Synonyms:** - beta-Thionase - Cystathionine Synthetase - Serine Sulfhydrase