The reactivation of heat-inactivated hyaluronidase.

1. Following heat denaturation after an hour at boiling temperature bovine testicular hyaluronidase has been shown to undergo spontaneous reactivation. 2. This reactivation is a function of the temperature at which the enzyme solution is maintained. 3. Secondary inactivation was observed to follow a reactivation of the enzyme at all concentrations observed. 4. There is a relationship between hydrolysis by the enzyme and the purity of the substrate. The demonstration of activity of the freshly boiled enzyme by the turbidimetric reduction technique is dependent upon the purity of the substrate. 5. These reactions have been demonstrated using preparations of bovine and avian hyaluronic acid and porcine chondroitin sulfate.