Gitlin D, Boesman M, Schmid K, Vuopio P
Science. 1968 May 3;160(3827):538-9. doi: 10.1126/science.160.3827.538.
The 3S (gamma1), 2S (gamma2), and 0.5S (gamma2) fractions of human plasma are heterogeneous in protein composition. Although each fraction contained a relatively small amount of protein antigenically related to the immunoglobulin light chains, most of the proteins were unrelated to immunogloublin G or its light chains. Of the 3S (gamma1)-globulins the greater part was immunochemically identical to carbonic anhydrase B and had carbonic anhydrase activity. These findings explain earlier reports of an immunochemical similarity between 3S (gamma1)-globulins and immunoglobulin light chains in spite of marked differences in amino acid and peptide composition between the two. Apparently not all plasma gamma-globulins are necessarily immunoglobulins.
