Crystalline low molecular weight gamma-globulin from a human urine.

A basic protein with a molecular weight near 17,000, related serologically to the normal serum gamma(2)-globulins, has been isolated in crystalline form from the urine of a patient with multiple myeloma. Proteins of this size along with the Bence-Jones molecules whose inolecular weight is about 35,000 can provide subunits for studies of the structure of the serum gamma-globulins.