Cystathionine gamma-lyase (or cystathionase) is an enzyme which breaks down cystathionine into cysteine and ?-ketobutyrate. The International Radiation Hybrid Mapping Consortium mapped the CTH gene to chromosome 1. The CTH gene had earlier been assigned to chromosome 16 by study of somatic cell hybrids. It is demonstrated that hydrogen sulfide (H2S) is physiologically generated by CTH.
