A mixture of venom and saliva from the lizard Heloderma horridum was analyzed for esterase, phosphomonoesterase, phosphodiesterase, 5'nucleotidase, and protease activities. Hydrolysis of N-benzoyl-L-arginine ethyl ester occurred at a pH optimum between pH 8.6 and 9.1 with a maximum activity of 452 units per mg per min. Hydrolysis of ptoluenesulfonyl-L-arginine methyl ester occurred at a pH optimum between pH 8.1 and 8.5 with a maximum of only 36 units per mg per min. One mg of the venom mixture liberated 9.3 μM of p nitrophenol from p-nitrophenyl phosphate per minute at an optimum pH between 8.2 and 8.3. Over a wide range of pH, only low phosphodiesterase and 5'nucleotidase activities were observed. A trace of caesinolytic activity occurred at pH 9.0.

Included in

Biochemistry Commons