3.1.6.4 3.3 4.2 pH 3.0: about 45% of maximal activity, pH 4.2: about 55% of maximal activity, hydrolysis of N-acetylgalactosamine 6-sulfate, 0.02 M acetate buffer 135655 3.1.6.4 5 6 purified recombinant enzyme 681958