[Physico-chemical characterisation and crystallisation of immunoglobulins and their fragments: a contribution to the three-dimensional structural elucidation of antibodies, IV. The Fab fragment and the Fc fragment of human immunoglobulin Kol; isolation and crystallisation (author's transl)].

The X-ray fine structure analysis of intact crystalline immunoglobulin Kol indicates that the conformation of the Fab region differs essentially from that determined for the free Fab fragment. For this investigation, the free Fab fragment Kol was prepared and characterised, and crystalline preparations of the whole protein were obtained, that were suitable for an elucidation of atomic structure, and the appropriate measurements were made. In the crystal structure analysis of immunoglobulin Kol, it has not been possible to determine the Fc region. The Fc fragment was therefore separated from the whole molecule to facilitate its study. The isolation of this Fc fragment, its characterisation and subsequent crystallisation are described.