ID 4.4.1.1 DE Cystathionine gamma-lyase. AN Cystathionase. AN Cystathioninase. AN Cysteine desulfhydrase. AN Cystine desulfhydrase. AN Gamma-cystathionase. AN Homoserine deaminase. AN Homoserine dehydratase. CA L-cystathionine + H(2)O = L-cysteine + NH(3) + 2-oxobutanoate. CF Pyridoxal 5'-phosphate. CC -!- The enzyme cleaves a carbon-sulfur bond, releasing L-cysteine and an CC unstable enamine product that tautomerizes to an imine form, which CC undergoes a hydrolytic deamination to form 2-oxobutanoate and CC ammonia. CC -!- The latter reaction, which can occur spontaneously, can also be CC catalyzed by EC 3.5.99.10. CC -!- Also catalyzes the conversion of L-homoserine to 2-oxobutanoate and CC ammonia, of L-cystine to thiocysteine, pyruvate and ammonia, and of CC L-cysteine to pyruvate, hydrogen sulfide and ammonia. CC -!- Formerly EC 4.2.1.15. PR PROSITE; PDOC00677; DR P55216, CGL2_CAEEL ; F4K5T2, CGL_ARATH ; Q58DW2, CGL_BOVIN ; DR Q55DV9, CGL_DICDI ; P32929, CGL_HUMAN ; Q60HG7, CGL_MACFA ; DR Q8VCN5, CGL_MOUSE ; Q19QT7, CGL_PIG ; P18757, CGL_RAT ; DR P31373, CYS3_YEAST ; Q59829, CYSA_STRCO ; O05394, MCCB_BACSU ; //