[N-acetyl-beta-D-glucosaminidase].

N-acetyl-beta-D-glucosaminidase (NAG), one of the glycolytic enzymes, is distributed in various tissue cells. Among them, the lysosome in the renal proximal tubular cells contains high amount of NAG. NAG is secreted in urine when kidney is damaged. Urinary NAG, therefore, is used as a marker which can detect the extent of the renal damage. Electrophoresis divides urinary NAG into three isozymes, pre A, A, and B forms. In normal males, the percentages of three isozymes are 12.3 +/- 5.56%, 73.15 +/- 4.77%, and 14.81 +/- 2.90%, respectively. In normal females, they are 12.87 +/- 4.70%, 65.47 +/- 4.61%, and 21.70 +/- 5.03%, respectively. The measurement of urinary NAG isozymes is useful to determine the type and severity of renal disease, especially renal tubular disease.