Occurrence of thiyl radical on a myosin derived from carp by superoxide anion radical

Abstract

The mechanism for the beneficial effects of vitamin C (L-ascorbic acid, AsA) on the quality of the heat-induced fish gel, kamaboko, has been proposed by Nishimura et al. to involve the production of thiyl radical (S·). The generation of S· in myosin by the superoxide anion radical (O 2), produced by the photo-activation of riboflavin, was then examined by electron spin resonance spectroscopy coupled with spin-trapping. Consequently, the production of S· was observed. This generation of S· in myosin was inhibited by the addition of 100 units (u)/ml superoxide dismutase (SOD), whereas heat-inactivated SOD, catatase (1,200 u/ml), and heat-inactivated catalase did not suppress the generation of S·. These results suggested that the generation of S· in myosin occurred due to the presence of O2-.