Cysteine-S-conjugate beta-lyase

Cysteine conjugate β-lyase is an enzyme activity found in various pyridoxal 5′-phosphate-dependent enzymes that can catalyze β-elimination of cysteine S-conjugates and selenocysteine Se-conjugates, generating reactive sulfur- or selenium-containing fragments, ammonia, and pyruvate[1][2][3][4]. In mammals, this activity is often not physiologically intended, but arises as a side reaction in aminotransferases and related enzymes[2][3]. The resulting metabolites can be excreted or, if chemically reactive, can cause cellular toxicity, including nephrotoxicity and carcinogenicity, through covalent modification of proteins and other macromolecules[2][3][4]. This metabolic pathway is particularly important for the activation and toxification of drugs, environmental pollutants, and naturally occurring compounds[2][3][4].

Other names

Cysteine conjugate β-lyaseCysteine-S-conjugate β-lyaseL-cysteine-S-conjugate thiol-lyase (deaminating; pyruvate-forming)Glutamine transaminase K/cysteine conjugate β-lyase

β-elimination of S-conjugated cysteine moieties resulting in formation of reactive intermediates; this can lead to drug bioactivation or toxification