The Bence-Jones protein of multiple myelomatosis: its methionine content and its possible significance in relation to the aetiology of the disease

Abstract

A case of multiple myelomatosis is described in which Bence-Jones proteinuria was found. The avg. daily output of protein was about 36 g. The output was not increased on adding 50 g. of the protein to the usual diet. A salting-out curve suggests that the protein consisted of 2 constituents in the proportion of about 90 and 10%. On electrophoretic analysis it gave one slightly asymmetrical peak which migrated with fibrinogen. The protein was shown to be free of methionine by paper chromato-graphic, microbiologic, biologic and 2 different chemical methods. The hydrolysate of protein, on chromatographic analysis, showed the presence of all the other common amino-acids, except hydroxy-proline. When supplemented with methionine, the protein was similar to casein in its ability to support the growth of rats. The qualitative and quantitative data presented are considered incompatible with the view that this Bence-Jones protein is synthesized by the body tissues. Their similarity to those in certain virus diseases is indicated, and it is suggested that multiple myelomatosis could be explained as a virus infection and the abnormal urinary protein as a constituent protein of that virus.