γ-glutamyltransferase

γ-glu·ta·myl·trans·fer·ase (GGT) (gloo″tə-məl-transґfər-ās) [EC 2.3.2.2] an enzyme of the transferase class that catalyzes the transfer of the γ-glutamyl group from glutathione to an amino acid to form a glutamyl–amino acid and the dipeptide cysteinyl-glycine. The enzyme occurs on the outside of the plasma membrane, primarily in cells of the kidney and other sites involved in transport; the glutamyl–amino acids formed can cross the membrane and enter the cell as part of the glutamyl cycle. Deficiency of the enzyme, an autosomal recessive trait, results in γ-glutamyl transpeptidase deficiency.