Separation and purification of myeloma proteins.
Three myeloma proteins, IgG lambda, IgA lambda and IgM lambda, were identified by protein electrophoresis (PEP), immunoglobulin quantitation and immunoelectrophoresis (IEP). Preparative block electrophoresis was generally carried out as an initial step to separate the myeloma proteins. The myeloma proteins thus separated were then passed through either diethylaminoethyl (DEAE) ion exchange chromatography and recycled in a Sephadex G-200 column, or first through gel filtration and recycled in DEAE. An attempt to bypass the step of preparative electrophoresis in the separation of IgG myeloma protein by passing the serum directly into a DEAE column was proved to be inappropriate. The IgM myeloma protein had a marked tendency to cryoprecipitate and to form euglobulin, and this property was utilized to separate the crude myeloma protein. The purified myeloma protein fractions were concentrated and dialyzed with Ultrafiltration (Amicon) and retested for purity with PEP, double diffusion (DD) and IEP. Some special physiochemical properties which affected the purification procedures are discussed.