2.7.3.6 6.5 7.7 pH 6.5: about 75% of maximal activity, pH 7.7: about 70% of maximal activity, reaction with phosphohypotaurocyamine 642487 2.7.3.6 7.7 9.5 pH 7.7: about 45% of maximal activity, pH 9.5: about 50% of maximal activity, phosphorylation of hypotaurocyamine 642487