Myeloma proteins occurrence

The immunoglobulins of normal mouse serum, in contrast to those of the human, contain L chains which are almost exclusively of the k type the concentration of X chains is about 3 to 5% of the total (43,44). This is reflected by the relative infrequency of occurrence of myeloma proteins of type X (45). 

We should note that some investigators are not satisfied that the existence of a switch mechanism, involving a change in class in immunoglobulin synthesized within a cell, has been completely established for normal cells all of the evidence is indirect. We find it difficult, however, to conceive of an alternative mechanism, in the case of multiple myeloma, to account for the repeated occurrence of myeloma proteins of different classes but shared idiotype within the same individual. 

Support for the aromatic h> othesis comes from model studies and protein crystal structure analysis. In biomimetic model studies, Dougherty has shown that cation-x interactions can stabilize both ground and transition states (44), and has used these results to predict the involvement of aromatic sidechains in receptors and enzymes that operate on cationic species (45,46). In the structural realm, the widespread occurrence of amino-aromatic interactions have been noted (47). In addition, a cocrystal structure shows that the myeloma protein McPC603 interacts with tile quaternary ammonium ion of its ligand phosphorylcholine through the... 

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