Abstract
As a result of studying the urine proteins of 223 individuals by starch gel electrophoresis, a new urine protein fraction has been recognized. On starch gel electrophoresis at alkaline pH the new fraction moves to a position appreciably nearer the cathode than the slowest-moving gamma-globulin in normal serum. A small amount of this post-gamma protein was found in the urine of 46 patients with clinical proteinuria, including 19 with the Fanconi syndrome and nine with multiple myeloma. The nature, origin, and clinical significance of post-gamma protein is discussed.