Enzymuria of the rat: the preparation of urine for enzyme analysis.

The effects of sample preparations by dialysis and gel filtration on the catalytic concentrations of alanine aminopeptidase, N-acetyl-beta-D-glucosaminidase, and beta-glucuronidase are described. Individual urines were collected during 24 hours on 3 consecutive days from 10 male rats. Gel filtration (Sephadex G25) was more effective than dialysis against water in the removal of inhibitors of N-acetyl-beta-D-glucosaminidase and beta-glucuronidase. For alanine aminopeptidase, slightly higher results were obtained by dialysis. Inhibitor contents varied from day to day. Activity decreases of beta-glucuronidase and N-acetyl-beta-D-glucosaminidase were found in some of the urine samples and interpreted as removal of activators. Gel filtration is recommended for the preparation of rat urine for the measurement of these three enzymes. The slightly inferior effect of gel filtration on alanine aminopeptidase should be disregarded for the sake of practicality.