3.1.13.3 additional information - active site highly acidic and substrate binding site highly basic 682781 3.1.13.3 7 9.5 pH 7.0: 50% of maximum activity, pH 9.5: 70% of maximum activity 134082 3.1.13.3 8 10 nitrophenyl uridine 5'-monphosphate, pH 8: about 15% of maximum activity, pH 10: about 10% of maximum activity 134081