N epsilon carboxymethyl lysine (CML or Carboxymethyl Lysine) is formed by the non enzymatic Schiff base reaction of glucose with proteins, followed by an Amadori rearrangement and oxidation that leaves only a carboxymethyl group attached to the lysine. The levels of CML adducts accumulate over time and have been used as an indicator of both serum glucose levels and oxidative protein damage.
Elevated serum CML modified proteins have been associated with diabetes and may contribute to diabetic retinopathy, nephropathy and angiopathy