One step separation of the sialoprotein possessing ABH and MN blood group activities from human red cell membrane

Sialoprotein possessing blood group activity has been usually extracted with organic solvents from red cell membrane. To obtain the blood group substance under milder condition, the author presented carboxymethyl (CM) cellulose column chromatography with eluents of phosphate buffer containing 1% Brij 35. Red cell stroma was applied onto the column with an equal volume of 0.0175 M phosphate buffer pH 6.3 and one-fifth volume of 0.05% 2-mercaptoethanol in 1% Brij 35. Separation of the substance was performed by stepwise elution with three kinds of phosphate buffers. Serological assay showed that only the first fraction eluted with 1% Brij 35 in 0.0175 M phosphate buffer pH 6.3 and ABH and MN blood group activities and the other fractions obtained with buffers of higher molarities had not such activities. Sialic acid was also detected only in the first fraction, and the majority of proteins of the stroma was found in the other fractions.