236 IMMUNO-CATALYSIS 



McClean and Hale (1940, 1941) reported a large amount of con- 

 firmatory experimental data regarding the various properties of 

 hyaluronidase, such as described above. They prepared purified en- 

 zymes from testicular extracts, CI. welchii, and CI. oedematis-maligni 

 (vibrion septique), and experimented with dried snake venom. These 

 preparations in high dilutions caused rapid diffusion in the skin, and 

 showed marked hyaluronidase activity as demonstrated by the reduc- 

 tion of viscosity and the liberation of N-acetylglucosamine. The op- 

 timal activity was at pH 4.6 which was also the pH of optimal activity 

 for the enzyme from all the sources examined. The activity for the 

 enzyme derived from bacteria falls below pH 4.6, and is slow above pH 

 4.6 up to 8.5. Viper venom enzyme was completely inactive above pH 

 6.5. 



The testicular enzyme did not reduce the viscosity of any of the 

 starch pastes (rice, maize, potato and wheat), but purified enzymes 

 derived from CI. welchii and vihrion septique reduced the viscosity of 

 both potato and wheat starch. The rate of the reaction bore no rela- 

 tion to their hyaluronidase activities. No Benedict reaction could be 

 obtained after 24 hr. incubation of starches with bacterial enzymes, 

 notwithstanding the substantial fall in viscosity that had occurred; 

 the iodine reaction also remained positive. Takadiastase, which con- 

 tains no hyaluronidase and does not diffuse in the skin, caused a rapid 

 fall in the viscosity of starch paste with the liberation of reducing 

 sugars. These findings showed that hyaluronidase has no amylase ac- 

 tivity. 



Hyaluronidase was found to have no action on disodium phenyl- 

 phosphate (for phosphatase) and diphenylphosphate (for phosphodi- 

 esterase). 



The enzymes either had no, or very slight, action on gastric mucin, 

 with the exception of those derived from CI. welchii and vihrion sep- 

 tique which liberated reducing substances from gastric mucin. This 

 confirms in part the observations of Meyer, et al., and contradicts those 

 of Robertson, et al. 



The question of whether or not heparin, closely allied to hyaluronic 

 acid in chemical structure, is attacked by hyaluronidase was inves- 

 tigated. It was found that viper venom, testicular or CI. welchii en- 

 zymes exercised no action on heparin; they do not, therefore, act 

 in a manner comparable with thrombokinase. 



