Diagnostic significance of different urinary enzymes in patients suffering from chronic renal diseases

The urinary enzymes alanine aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.2), N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30), and ribonuclease (EC 3.1.4.22) were measured in 66 healthy persons and 52 patients suffering from chronic renal diseases (pyelonephritis, glomerulonephritis). The residual renal function of patients characterized by 99mTc-diethylenetriaminopentaacetate isotope clearance was only moderately reduced. Except for gamma-glutamyltransferase, patients generally showed increased urinary enzyme excretions. N-Acetyl-beta-D-glucosaminidase was more sensitive to detect renal dysfunction than the other enzymes and the conventional parameters serum creatinine, total protein excretion, and the measurement of glomerular filtration rate. The determination of this enzyme can be recommended as a suitable diagnostic parameter in nephrology.