Abstract
1. The activities of beta-galactosidase, beta-glucosidase, beta-glucuronidase and N-acetyl, beta-glucosaminidase were estimated in normal and pathological rat urine, with 4-methylumbelliferyl glycosides as substrates. 2. Kidney damage induced by injections of uranium nitrate, mercuric chloride, potassium dichromate or 4-nitrophenylarsonic acid causes a marked increase in the urinary excretion of all four enzymes. 3. The rise in beta-glucosidase activity was associated with the appearance of a new urinary enzyme species, which was examined by starch-gel electrophoresis, DEAE-cellulose chromatography and filtration on Sephadex G-75 and G-200. 4. This enzyme appears to be identical with its counterpart in the kidney, and it is suggested that it arises in the urine as a result of renal tubular breakdown. 5. The other glycosidases examined also show some physical similarities to the corresponding enzymes of the rat kidney.