Conversion of Amadori product of Maillard reaction to Nϵ‐(carboxymethyl)lysine in alkaline condition

Abstract
N ϵ‐(carboxymethyl)lysine (CML) is known to be formed by oxidative cleavage of Amadori products between C‐2 and C‐3 of the carbohydrate chain. We report here that CML formation from Amadori compounds is highly accelerated under alkaline conditions. Incubation of glycated human serum albumin (HSA) in 0.1 N NaOH led to the formation of CML whereas glycated HSA reduced by NaCNBH3 or non‐glycated HSA did not generate CML. N α‐t‐butyloxycarbonyl‐N ϵ‐fructoselysine (Boc‐FL), a model compound of Amadori product, was converted to CML under alkaline conditions. CML level of human sera (n=224) preincubated with 0.1 N NaOH correlated well with glycated albumin value (r=0.912) and hemoglobin A1c (r=0.797).