Mucolytic Enzyme Systems XIII. Effect of Compounds on Hyaluronidase and its Inhibition by Human Serum. ∗

Summary

Modifications in the preparation of the substrate for the measurement of hyaluronidase activity by the viscosity method have been described. Increased sensitivity in the measurement of both the enzyme and its inhibitors has resulted, and spontaneous depolymerization of the substrate on storage has been virtually eliminated. The effect of the use of veronal and phosphate buffers in the substrate solution has been investigated, and the influences of a range of concentrations of magnesium and phosphate ions on both hyaluronidase and its serum inhibitor have been determined.

Evidence has been presented to indicate a possible role of sulfhydryl groups in both the enzyme and inhibitor actions. Cysteine and glutathione have been shown to cause a depolymerization of hyaluronic acid.

Methionine, cyanide, azide, histamine, benedryl, and toluidine blue have been found to both inactivate the serum inhibitor and inhibit hyaluronidase. Certain implications have been discussed.

Adrenocorticotrophic hormone has been shown to have negligible effect, in vitro, on either hyaluronidase or its serum inhibitor.