gamma-glutamyl cycle

γ-glu·tam·yl cy·cle

a proposed pathway for the glutathione-dependent transport of certain amino acids (most notably l-cystine, l-methionine, and l-glutamine) and dipeptides into certain cells; this cycle requires the formation of γ-glutamyl amino acids and γ-glutamyl dipeptides as well as a protein for the translocation of these di- and triisopeptides into the cells.