EVALUATION OF PROTEOLYTICALLY RELEASED CARBOHYDRATE-CONTAINING PEPTIDES OF BOVINE PROTHROMBIN FRAGMENT-1 USING ELECTROSPRAY-IONIZATION MASS-SPECTROMETRY AND CAPILLARY ELECTROPHORESIS

Described here is a method used to determine the sialic acid content o f the structurally distinct carbohydrates attached at N77 and N101 of bovine prothrombin fragment 1. The protein is proteolytically cleaved with alpha-chymotrypsin to release two glycopeptides, each containing one of the two glycosylation sites. Electrospray ionization mass spect rometry and capillary electrophoresis are used to determine the struct ural difference between the carbohydrates of each of these glycopeptid es. N77 bears a carbohydrate containing as many as 4 sialic acid (N-ac etylneuraminic acid) residues, whereas the carbohydrate attached at N1 01 may carry as many as 5 sialic acid residues.