2.6.1.45 5 7 - 723450 2.6.1.45 6 9 approx. 60% of maximal activity at pH 6, approx. half-maximal activity at pH 9 636690 2.6.1.45 7 - gradual decrease in activity above 723450 2.6.1.45 7.5 9.2 approx. 50% activity at pH 7.5 and 9.2, no activity below pH 6.7 and above pH 9.9 636689