Abstract
1. A collagenase digest of rat kidney cortex was separated into four bands by zonal centrifugation. 2. Two of these bands were shown by light-microscopy to contain glomeruli and tubular fragments, which were free from each other and well separated from other renal material. 3. Protein, N-acetyl-beta-glucosaminidase, 5'-nucleotidase, l-leucine beta-naphthylamidase, leucine aminopeptidase, acid phosphatase and alkaline phosphatase were assayed across the gradient. 4. The greater proportion of these enzyme activities was recovered in the tubular fragments and acid phosphatase was the only enzyme detected in significant amounts in the glomeruli. 5. Tubular fragments and glomeruli were sedimented and multiple forms of beta-naphthylamidase, N-acetyl-beta-glucosaminidase, acid phosphatase and alkaline phosphatase were investigated by starch-gel electrophoresis.