Effect of sulfated compounds on acid sialidase

The inhibitory effects of various sulfated compounds on the activities of sialidases purified from porcine liver and human placenta were investigated. Among the sulfated compounds tested, heparin, dextran sulfate, condroitin sulfates and sulfatide significantly inhibited the 4-methylumbelliferyl-alpha-N-acetylneuraminic acid (4-MU-NeuAc) sialidase activities of the two enzyme preparations, but glucose 6-sulfate and glucosamine 6-sulfate did not. Potassium sulfate showed an inhibitory effect only at high concentrations. When the sialidase activities were measured using natural substrates, the sialidase activities for the (alpha2-3) and (alpha2-6) sialyllactoses, and colominic acid, were markedly inhibited by heparin and sulfatide similar to 4-MU-NeuAc, although the fetuin sialidase activity was not significantly influenced by them. The sialidase activity hydrolyzing GM3 was strongly inhibited by heparin, but not by sulfatide.