FOOD SCIENCE ›› 2006, Vol. 27 ›› Issue (4): 37-40.

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Inhibitory Effect on Potato Polyphenol Oxidase Activity by L-Cysteine

 QIU  Long-Xin, HUANG  Hao, CHEN  Qing-Xi   

  1. 1.The Key Laboratory of Ministry of Education for Cell Biology and Tumor Cell Engineering, Department of Biochemistry and Biotechnology, Xiamen University, Xiamen 361005, China;2.Department of Biology Science and Engineering, Longyan University, Longyan 364000, China
  • Online:2006-04-15 Published:2011-09-13

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Abstract:  In this paper, L-Cysteine was discovered to have a strong inhibition on potato polyphenol oxidase activity. The existence of L-Cysteine resulted in prolonging the lag time of the enzyme reaction, while the steady-state rate of the enzyme activity decreased with the increase of concentration of L-Cysteine. The IC50, inhibitor’s concentration leading to 50% activity lost, was estimated to be 100μmol/L. The inhibition kinetics and mechanism of L-Cysteine on the potato PPO activity have been studied. The results showed that inhibition of L-Cysteine on the enzyme is an irreversible reaction. It has a direct effect on the enzyme activity, which inhibit the production of o-quinones to stop the enzymatic browning of potato.

Key words:  , potato； polyphenol oxidase； L-Cysteine； inhibition kinetics；