Isolation and characterization of two beta1-glycoproteins of human serum.

Two immunoelectrophoretically defined, heretofore unidentified beta(1)-globulins of human serum, provisionally designated beta(1C)- and beta(1A)-globulin, were isolated by means of preparative electrophoresis and chromatography on anion exchange cellulose. The sedimentation coefficient S(0) (20, w) of beta(1C)-globulin was shown to be 9.5 S, and that of beta(1A)-globulin, 6.9 S. Both proteins were found to contain similar amounts of carbohydrate, to be devoid of lipids, and to possess the solubility characteristics of euglobulins. In the Ouchterlony double diffusion test they gave the reaction of partial identity, which revealed beta(1A)-globulin to be anti-genically deficient as compared to beta(1C)-globulin. beta(1A)-globulin could not be detected in fresh sera and beta(1C)-globulin was absent from aged sera. Highly purified beta(1C)-globulin stored at 1 degrees C. was converted to beta(1A)-globulin within 4 to 6 weeks, and at 37 degrees C. was converted within 6 days. The likelihood of a dimer-monomer relationship between these two proteins was discussed.