Glycophorins of Bovine Erythrocyte Membranes. Isolation and Preliminary Characterization of the Major Component

Abstract

Crude glycophorin fraction was prepared from bovine erythrocyte membranes by extraction with lithium diiodosalicylate and partition in aqueous phenol. The crude fraction was further separated into three fractions by gel chromatography and ionexchange chromatography. The major fraction, designated glycophorin BA, accounts for 80% of the crude fraction. Its carbohydrate content was 79% by weight including galactose, N-acetylgalactosamine, N-acetylglucosamine and N-glycolylneuraminic acid. Iodosobenzoate treatment of glycophorin BA produced two fragments; one is a highly glycosylated segment and the other a hydrophobic peptide. The amino-terminal sequence of the hydrophobic peptide representing the carboxylterminal half of glycophorin BA was determined.
The other two fractions, IIIa and IIlb, were still heterogeneous when analyzed by gel electrophoresis. Fraction IIIa contained two glycophorins having apparent molecular weights of 46, 000 and 42, 000, while fraction Illb contained a glycoprotein having a marked tendency to aggregate.