研究了二氢杨梅素对酪氨酸酶的单酚酶和二酚酶抑制作用和机理.结果表明,二氢杨梅素对单酚酶、二酚酶的抑制率分别为95.87％、69.01％;二氢杨梅素对单酚酶的抑制作用表现为酶催化反应的迟滞时间延长；二氢杨梅素对二酚酶的抑制作用表现为可逆混合型抑制,对游离酶的抑制常数(K1)和对酶-底物络合物的抑制常数(KIS)分别为150 μmol·L-1和83μmol·L-1.二氢杨梅素可作为天然的酪氨酸酶抑制剂.%The inhibitory effects and inhibiting mechanism of dihydromyricetin(DMY) on the activity of mnophenolase and diphenolase contained in tyrosinase was studied.The results indicated that DMY could obviously inhibit the activities of monophenolase and diphenonase,and the inhibition rates were 95.87％and 69.01％,respectively.DMY can extend the lag time of monophenolase for oxidation of L-tyrosinase.The inhibition kinetics analyzed by Lineweaver-Burk plots showed DMY was reversibility and mixed inhibition for the oxidation of L-Dopa.The equilibrium constants for inhibitor binding with free enzyme K1 and with enzyme-substract complex KIS were 150μmol·L-1 and 83μmol·L-1,respectively.DMY could be used as natural tyrosinase inhibitor.
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