Accepted name: glutathione-specific γ-glutamylcyclotransferase
Reaction: glutathione = L-cysteinylglycine + 5-oxo-L-proline
Other name(s): γ-GCG; CHAC (gene name); CHAC1 (gene name); CHAC2 (gene name)
Systematic name: glutathione γ-glutamyl cyclotransferase (5-oxo-L-proline producing)
Comments: The enzyme, found in bacteria, fungi and animals, is specific for glutathione (cf. EC, γ-glutamylcyclotransferase). The enzyme acts as a cyclotransferase, cleaving the amide bond via transamidation using the α-amine of the L-glutamyl residue, releasing it as the cyclic 5-oxo-L-proline.
1.  Kumar, A., Tikoo, S., Maity, S., Sengupta, S., Sengupta, S., Kaur, A. and Bachhawat, A.K. Mammalian proapoptotic factor ChaC1 and its homologues function as γ-glutamyl cyclotransferases acting specifically on glutathione. EMBO Rep. 13 (2012) 1095–1101. [PMID: 23070364]
2.  Kaur, A., Gautam, R., Srivastava, R., Chandel, A., Kumar, A., Karthikeyan, S. and Bachhawat, A.K. ChaC2, an enzyme for slow turnover of cytosolic glutathione. J. Biol. Chem. 292 (2017) 638–651. [PMID: 27913623]
[EC created 2017]