ID 4.2.1.22 DE Cystathionine beta-synthase. AN Beta-thionase. AN Methylcysteine synthase. AN Serine sulfhydrase. CA L-serine + L-homocysteine = L-cystathionine + H(2)O. CF Pyridoxal 5'-phosphate. CC -!- A multifunctional enzyme: catalyzes beta-replacement reaction between CC L-serine, L-cysteine, cysteine thioethers or some other beta- CC substituted alpha-L-amino acids and a variety of mercaptans. CC -!- Formerly EC 4.2.1.21. PR PROSITE; PDOC00700; DR Q2V0C9, CBS_APIME ; P46794, CBS_DICDI ; P35520, CBS_HUMAN ; DR Q58H57, CBS_MACFA ; Q91WT9, CBS_MOUSE ; Q9N0V7, CBS_RABIT ; DR P32232, CBS_RAT ; P32582, CBS_YEAST ; Q9YBL2, CYSO_AERPE ; DR P9WP50, Y1077_MYCTO; P9WP51, Y1077_MYCTU; //