Concentration of acid phosphatase, ribonuclease, desoxyribonuclease, beta-glucuronidase, and cathepsin in droplets isolated from the kidney cells of normal rats.

1. Three fractions of "droplets" having diameters of 1 to 5 micro (fraction I), 0.5 to 1.5 micro (fraction II), and 0.1 to 1.0 micro (fraction III) were isolated from the kidney cells of normal rats. 2. All three "droplet" fractions showed 10 to 15 times higher activities of acid phosphatase, beta-glucuronidase, ribonuclease, desoxyribonuclease, and cathepsin than the total homogenate and the mitochondrial fraction. 3. After a rough fractionation of the total homogenate, approximately 50 per cent of the 5 enzymes was found in the fractions which contained the "droplets" and approximately 30 per cent in the supernatant fluid. 4. The similarities between the enzymatic properties of the "droplets" from kidney cells and of the fractions isolated from liver cells by other investigators have been discussed.