Identification of N-omega-carboxymethylarginine, a new advanced glycation endproduct in serum proteins of diabetic patients: Possibility of a new marker of aging and diabetes

A new advanced glycation end product (AGE), N-omega-carboxymethyl-arginine (CMA), was found in acid-soluble skin collagen of a newborn bovine prepared by in vitro glycation with 1 M glucose incubation at 37 degreesC for about 30 days [1]. CMA production was increased with incubation time in parallel , and after 30 days incubation the yield was 100 times higher than that of pentosidine [1]. This result suggested the importance of CMA as a major AGE in collagen. We have detected and measured the CMA level in human serum pr oteins by electrospray ionization/liquid chromatography/mass spectrometry ( ESI/LC/MS), using CMA standard concentration curve. In this report, we firs t show the existence of CMA in vivo, and its serum level is significantly e levated in diabetic serum proteins, compared to age-matched control serum p roteins. These results provide strong evidence that CMA is a new diagnostic marker of glycation in diabetes. (C) 2001 Academic Press.