Abstract
A protein having Mr of more than 900K (900, 000) was isolated by chromatography on a column of Sepharose 4B coupled with solubilized elastin, followed by sucrose density gradient centrifugation. The protein is composed of several disulfide-linked subunits. SDS-polyacrylamide gel electrophoresis and immunoblotting indi-cated that two of the subunits are identical with the heavy chains of IgM and IgG, and one is immunologically related to the heavy chain of IgA. The results sug-gested that this protein is a new protein that belongs to the category of, or is closely related to, the immunoglobulins. As described in the succeeding paper, it has cell-binding activity (Fukamizu et al. (1986) J. Blocliem. 100, 843-848). We tentatively refer to this protein as “cell-binding immunoglobulin-like protein (CIP).”
