[Physico-chemical characterisation and crystallisation of immunoglobulins and their fragments: a contribution to the three dimensional structural determination of antibodies, III. Human immunoglobulin Kol, a myeloma protein of the type IgG, gamma2 kappa2, Gm (f)+. Comparative studies on dissolved and crystalline material (author's transl)].

Immunoglobulin Kol has been isolated and characterised as the intact molecule, which consists of an antigen binding part (Fab) and the C-terminal fragment (Fc). Crystals of the protein are suitable for X-ray diffraction resolution of the fine structure, down to atomic dimensions; but this does not permit the representation of the Fc-part of the molecule. The following studies were performed on the protein in solution before and after crystallisation; the results were the same in both cases, thus showing that crystallisation does not alter the molecule: After enzymic cleavage of the protein, the products were isolated and identified by immunological reactions and by analytical ultracentrifugation; the behaviour of the protein in disc electrophoresis following reductive cleavage was also studied.