| 7849640 |
Terato H, Yamamoto O: Hydrated electron-induced inactivation of tyrosinase in aqueous solution by exposure to cobalt-60 gamma-rays. Biochem Mol Biol Int. 1994 Sep;34(2):295-300.
I. Cresolase activity.. Tyrosinase (0.2 mg/ml of 0.1 M phosphate buffer solution, pH 6.5) which has cresolase and catecholase activities was irradiated with 60Co gamma-rays. The cresolase activity was measured at varying radiation doses under various atmospheric conditions. D0 was found to be 350 Gy in N2-saturated solution. The OH radical has been shown to be the main species involved in radiation-induced enzyme inactivation. However, in this study, OH radical scavengers, t-BuOH and MeOH, had no effect. O2 which acts generally as an enhancer of OH-induced enzyme inactivation also had little effect, but N20 ae aq scavenger, and Cu++ markedly inhibited the inactivation indicating that e aq is the main species involved in inactivating the cresolase activity, reducing Cu++ as the active center. |
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