Recombination Experiments with an Unusual L-Chain Related Myeloma Protein

The occurrence of a light chain related myeloma protein, which was defective compared with complete light chains, gave rise to further investigation of its structure. Mixing of 125I-labelled polypeptide chains resulting from the reduction of this protein with heavy and light polypeptide chains of an 131I-labelled myeloma protein showed recombination to a considerable extent. Fragments of L-chains, as it appears from these experiments, may exist as dimers stabilized by noncovalent bonds. Their interaction with light and heavy chains in vivo might compete with the normal assembly of immunoglobulin polypeptide chains.