Isolation and characterization of two glycophorins from horse erythrocyte membranes

Crude glycophorin fraction was prepared from horse erythrocyte membranes by extraction with lithium diiodosalicylate and partition in aqueous phenol. Two glycophorins, designated glycophorins HA and HB, were isolated by two different techniques: preparative gel electrophoresis in the presence of sodium dodecyl sulfate and ion-exchange chromatography in the presence of the nonionic detergent Ammonyx LO. Each glycophorin formed at least two bands on gel electrophoresis, which corresponded to a dimeric form and a monomeric form. Glycophorin HA, the major component, had a blocked amino-terminus and consisted of 70% protein and 30% carbohydrate. Glycophorin HB, the minor component, had threonine as the amino-terminus and consisted of 80% protein and 20% carbohydrate. Since glycophorin HB showed a chemical composition distinct from that of glycophorin HA, glycophorin HB was not a partially degraded form of glycophorin HA.