Hydrated electron-induced inactivation of tyrosinase in aqueous solution by exposure to cobalt-60 gamma-rays. I. Cresolase activity

Hiroaki Terato, O. Yamamoto

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Abstract

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. Do 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 N2O a e(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.

Original languageEnglish
Pages (from-to)295-300
Number of pages6
JournalBiochemistry and Molecular Biology International
Volume34
Issue number2
Publication statusPublished - Jan 1 1994
Externally publishedYes

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ASJC Scopus subject areas

  • Biochemistry
  • Genetics
  • Molecular Biology

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