Comparative kinetic studies on mouse & bovine testicular hyaluronidases
Gupta, G.S.; Goldberg, E.
Indian Journal of Biochemistry and Biophysics 17(6): 443-447
1980
ISSN/ISBN: 0301-1208 PMID: 7251032 Document Number: 167651
Partially purified mouse testicular hyaluronidase was characterized and compared with bovine testicular hyaluronidase. The mouse enzyme has an optimum pH of 4.3 with a broad pH spectrum similar to that of bovine testicular hyaluronidase. While bovine and mouse testicular hyaluronidases show maximum activity at 37.degree. C, different values for energy of activation are obtained from Arrhenius plots for degradation of hyaluronic acid. Mouse hyaluronidase has a Km value of 0.9 mg/ml as compared to 2.1 mg/ml for the bovine enzyme. Thermal denaturation experiments reveal that the mouse testicular enzyme is more stable than the bovine enzyme at 55.degree. C. Mouse testicular hyaluronidase is inhibited by CuSO4 (10-3 M), HgCl2 (10-4-10-3 M) and para-chloromercuribenzoic acid (10-4-10-3 M), and is activated by NaCl (0.4 M), CuSO4 (10-5 M), FeSO4 (10-4-10-3 M), ZnSO4 (10-4-10-3 M) and MgCl2 (10-4 M). The most potent inhibitors for mouse testicular hyaluronidase are CuSO4 and HgCl2 at 10-3 M concentration. Cysteine appeared to protect the enzyme inhibition caused by HgCl2.