An enzyme that catalyzes the synthesis of pyroglutamate from a gamma-glutamyl-amino acid, also releasing the free amino acid. The enzyme acts on derivatives of glutamate, 2-aminobutyrate, alanine and glycine. The enzyme has been proposed to have a role in a gamma-glutamyl cycle for amino acid transport into cells in the intestines. EC 2.3.2.4.

Synonyms: gamma-Glutamylcyclotransferase gamma-Glutamylamine Cyclotransferase EC 4.3.2.9 gamma Glutamylamine Cyclotransferase (5-L-Glutamyl)-L-amino-acid 5-glutamyltransferase (cyclizing) gamma Glutamylcyclotransferase Cyclotransferase, gamma-Glutamylamine