Chinese Journal of Applied Chemistry

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Inhibition Effect of Vanadate-replaced Polyoxometalates on Mushroom Tyrosinase

ZHENG Aping1, CHEN Bingnian2, CHEN Fahe1, WANG Li1*   

  1. (1.School of Bioengineering,Jimei University,Xiamen 361021,China;
    2.Yanwu Affiliated Hospital of Zhongshan Hospital Xiamen University(Xiamen University Hospital),Xiamen 361005,China)
  • Received:2012-04-18 Revised:2012-05-31 Published:2013-02-10 Online:2013-02-10
  • Contact: wang li

Abstract: Three kinds vanadate-replaced polyoxometalates, α-1,2,3-K6H[SiW9V3O40], α-1,2-K6[SiW10V2O40] and α-K5[SiW11VO40](abbreviated as α-SiW9V3, α-SiW10V2, α-SiW11V) were synthesized and evaluated as tyrosinase inhibitors using the enzymological kinetic method. The results demonstrate that α-SiW9V3 can inhibit tyrosinase strongly, as demonstrated by the inhibition of the steady-state activity of the enzyme and the lengthening of the lag time. The IC50 of α-SiW9V3 was estimated to be 0.6841 mmol/L for the inhibition of mushroom tyrosinase. It resulted in the lag time of the monophenolase extension from 235 s to 650 s with 0.7 mmol/L of α-SiW9V3. The inhibition of α-SiW9V3 on monophenolase of mushroom tyrosinase proceeds as reversible process, and the inhibition of α-SiW9V3 is a competitive-uncompetitive mixed-Ⅱ type due to the oxidation of L-tyrosine. The inhibition constants(KI and KIS) are determined to be 4.22 mmol/L and 2.39 mmol/L, respectively. As for the α-SiW10V2, however, it is unsoluble in DMSO buffer, and its effect on the mushroom tyrosinase cannot be studied. While the inhibition ability of α-SiW11V on tyrosinase activity is rather weak.

Key words: polyoxometalate, mushroom tyrosinase, monophenolase activity, Inhibition effect

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