Interest and research in urinary enzymology were incited about three decades ago by reports that urinary enzymes are elevated in diseases of the kidney and urinary tract. Of the more than 40 hydrolases, oxidoreductases, transferases, and lyases identified in human and animal urine, only ten or so are being used as diagnostic indicators. Recognition of the quantitative distribution of enzymes in the various anatomical and functional parts of the nephron and advances in our understanding of the handling of proteins by the kidney have made it possible to associate urinary enzyme activity...