Human serum albumin is a single chain polypeptide which
composes about 60% of the plasma proteins. In normal serum
approximately 10% of the albumin is modified by non-enzymatic
glycosylation which occurs primarily on lysine residue number
525 (Garlick & Mazer, J. Biol. Chem., 258, 6142-6146, 1983).
The amount of glycosylated albumin in serum is markedly
elevated in diabetes (Dolhofer & Wieland, Febs. Lett., 103,
282-286, 1979) and thus its determination may help in the
monitoring of the disease. Studies also show that
glycosylation of the protein alters its properties and this
modification causes it to be ingested by endothelial cells in
preference to unmodified albumin (Williams, et al,
Proc. Natl. Acad. Sci, 78, 2393-2397, 1981).