Effects of the glycoprotein sugar chains on the amino-carbonyl reaction of chicken and Japanese quail ovomucoids with glucose.

The amino-carbonyl reactions of two glycoproteins, chicken ovomucoid and quail ovomucoid, which have similar amino acid sequences but different sugar chains, were compared. The free guanidino groups, but not amino groups, of chicken ovomucoid decreased more rapidly than those of quail ovomucoid during reaction with glucose. Protein polymerization and formation or brownish or fluorescent compounds also occurred more quickly in the chicken ovomucoid. These results suggested that the sugar chain moieties affect the amino-carbonyl reaction of glycoproteins with deducing sugars, especially at advanced stages of the reaction.