The Glycosylation of Hemoglobin: Relevance to Diabetes Mellitus

Abstract

Glucose reacts nonenzymatically with the NH 2 -terminal amino acid of the β chain of human hemoglobin by way of a ketoamine linkage, resulting in the formation of hemoglobin A Ic . Other minor components appear to be adducts of glucose 6-phosphate and fructose 1,6-diphosphate. These hemoglobins are formed slowly and continuously throughout the 120-day life-span of the red cell. There is a two- to threefold increase in hemoglobin A Ic in the red cells of patients with diabetes mellitus. By providing an integrated measurement of blood glucose, hemoglobin A Ic is useful in assessing the degree of diabetic control. Furthermore, this hemoglobin is a useful model of nonenzymatic glycosylation of other proteins that may be involved in the long-term complications of the disease.