Glutamate Cysteine Ligase, Modifier Subunit (GCLM)

Glutamate-cysteine ligase, also known as gamma-glutamylcysteine synthetase, is the first rate limiting enzyme of glutathione synthesis. The enzyme consists of two subunits, a heavy catalytic subunit and a light regulatory subunit. Gamma glutamylcysteine synthetase deficiency has been implicated in some forms of hemolytic anemia.

It catalyses the ATP-dependent condensation of cysteine and glutamate to form the dipeptide gamma-glutamylcysteine. The peptide bond in this peptide product is between the carboxylate group of the glutamate and the amino group of the cysteine.The product of the GCL-mediated condensation reaction of L-glutamate and L-cysteine is gamma-glutamylcysteine, which is readily condensed with glycine, by glutathione synthetase, to form glutathione.