Identification and isolation of calcium-dependent and -independent bovine immunoglobulins reactive with Sepharose 4B.

Calcium-dependent and -independent Sepharose 4B-binding bovine serum proteins were isolated by affinity chromatography on unsubstituted Sepharose 4B using 2 mM ethylenediamine tetraacetic acid followed by 0.1 M galactose. They appeared in two different protein peaks by gel filtration on Sephacryl S-200. The earlier eluted protein was demonstrated to be immunologically IgM, whereas the retarded one IgG. From these findings, Sepharose 4B-binding bovine serum proteins are suggested to be calcium-dependent and -independent immunoglobulins IgM and IgG.