Glycosylated proteins as an indicator of metabolic control in diabetes: evaluation by aminophenylboronic acid affinity chromatography.

Glycosylated proteins, glycosylated albumin and HbA1 were studied in type I and type II diabetes. Glycosylated proteins were evaluated by a new method: aminophenylboronic acid affinity chromatography. A good correlation was found between total HbA1 and glycosylated proteins in both groups (r = 0.57, p less than 0.05; r = 0.67, p less than 0.01, respectively), but a positive correlation between stable HbA1 and glycosylated proteins was present only in maturity onset diabetics (r = 0.71, p less than 0.01). Glycosylated proteins correlated with glycosylated albumin only in type II diabetes (r = 0.67, p less than 0.01). We hypothesize that in maturity onset diabetes glycosylated proteins and HbA1 reflect a greater glycemic stability while in insulin-dependent diabetes the same proteins reflect a different periodic pattern of glycemic control. Moreover, our data suggest that aminophenylboronic acid affinity chromatography is a suitable tool for routine monitoring of metabolic control in maturity onset diabetes, while further investigations are needed to establish if this method is a useful index of altered glucose metabolism in type I diabetes.