Some physico-chemical and serological properties of isolated protein components of red cell membranes

Exposure of human red cell ghosts to low pH (pH 2–2·2) for 20–24 hr and extraction with a biphasic system (butanol–water) at acid pH yielded a water-phase material which was separated by gel filtration into two major fractions. Fraction A is of glycoprotein nature having a molecular weight of approximately 200,000 and exhibiting A, M and N antigen activity. Fraction B is primarily protein in nature having a molecular weight of about 50,000 to 60,000, and is practically devoid of A and MN antigens.

The materials isolated were found heterogeneous by electrophoresis in urea starch gels. Peak A and peak B differed significantly with respect to number, mobility, and intensity of the separated components.

The physico-chemical and serological properties of the water phase and its sub-fractions are discussed with respect to structural make-up of erythrocyte membrane.