title: A simple and sensitive radiochemical assay for plasma guanase.
abstract: A simple and sensitive radiochemical micro-assay has been developed for the determination of plasma guanase activity. The method is based upon the measurement of the conversion of 14C-labeled guanine to xanthine, catalysed by the enzyme guanase (guanine aminohydrolase;EC 3.5.4.3). Using this method, the catalytic activity in the plasma of adult healthy controls was 0.040 +/- 0.09 nmol/h.mg protein (x +/- s). In children under 5 years of age higher levels of enzyme activity were demonstrated. In adult patients with liver disease plasma guanase activities were found to be 3 to 7-fold increased as compared to the normal adult mean value.
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000619:Aminohydrolases / Q000097:blood*; D002384:Catalysis; D002648:Child; D002675:Child, Preschool; D006148:Guanine Deaminase / Q000097:blood*; D006525:Hepatitis, Viral, Human / Q000201:enzymology; D006801:Humans; D008103:Liver Cirrhosis / Q000201:enzymology; D011854:Radiochemistry / Q000379:methods*
chemical_list: D000619:Aminohydrolases; D006148:Guanine Deaminase