gamma-Glutamylamine cyclotransferase: specificity toward epsilon-(L-gamma-glutamyl)-L-lysine and related compounds.

gamma-Glutamylamine cyclotransferase, an enzyme that catalyzes the conversion of L-gamma-glutamylamines to free amines and 5-oxo-L-proline, was found in rabbit kidney and in various other tissues. The specificity of this enzyme indicates that it functions in the metabolism of products of transglutaminase action; among its substrates are epsilon-(L-gamma-glutamyl)-L-lysine, a derivative of this peptide in which the alpha-amino and carboxyl groups of the lysine moiety are blocked, and L-gamma-glutamyl-polyamine derivatives.