Purification of human alpha 1-beta glycoprotein and study of its microheterogeneity and molecular variants

Alpha 1-beta glycoprotein (A1B) was purified to homogeneity from human plasma using a three-step procedure involving pseudo-ligand affinity chromatography on immobilized Cibacron Blue 3-GA, gel filtration chromatography on Sephadex G-200 and ion-exchange chromatography on DEAE Affigel Blue. The overall yield of the combined techniques was 31%. The major advantages of this technique include its conveniency, and the fact that no apparent alteration of the purified protein occurred as judged by the absence of modification of its physicochemical parameters. A1B appears to be present in normal plasma as a major form of Mr 70,000 daltons with extensive charge heterogeneity, together with minor components of higher Mr.