We recently hypothesized that increased gamma-glutamyltransferase and aminopeptidase N levels reflect a cell’s adaptive response to intracellular glutathione deficiency found in T2D, and that an increase in these enzyme levels is required to promote extracellular peptide degradation, providing amino acid precursors for de novo GSH biosynthesis [240]. The gene discussed is ANPEP; the disease is type 2 diabetes mellitus.