钒取代的Dawson型磷钼酸对酪氨酸酶的抑制作用

采用酶动力学方法研究了5种钒取代的Dawson型磷钼酸H₇P₂Mo₁₇VO₆₂]、H₈P₂Mo₁₆V₂O₆₂]、H₉P₂Mo₁₅V₃O₆₂]、H₈P₂Mo₁₄V₄O₆₂H₂]和H₉P₂Mo₁₃V₅O₆₂H₂](分别简写为P₂Mo₁₇V、P₂Mo₁₆V₂、P₂Mo₁₅V₃、P₂Mo₁₄V₄和P₂Mo₁₃V₅)对蘑菇酪氨酸酶二酚酶的抑制作用,结果表明,效应物P₂Mo₁₇V、P₂Mo₁₆V₂和P₂Mo₁₅V₃能够明显地抑制酪氨酸酶的活性,其半抑制浓度(IC₅₀)值分别为0.409、0.386和0.386 mmol/L,且均表现为可逆的竞争型抑制,效应物P₂Mo₁₇V、P₂Mo₁₆V₂和P₂Mo₁₅V₃对游离酶的抑制常数K_I分别为0.234、0.391和0.249 mmol/L。 而效应物P₂Mo₁₄V₄在0~1.0 mmol/L浓度范围内,对酪氨酸酶二酚酶无明显抑制作用,效应物P₂Mo₁₃V₅对酪氨酸酶二酚酶表现为激活作用。

Inhibitory Effect of Vanadium-Substituted Dawson Type Phosphomolybdic Acid on Tyrosinase

In this paper, the inhibitory effects of five Dawson type phosphomolybdic acids, e.g., H₇P₂Mo₁₇VO₆₂], H₈P₂Mo₁₆V₂O₆₂], H₉P₂Mo₁₅V₃O₆₂], H₈P₂Mo₁₄V₄O₆₂H₂] and H₉P₂Mo₁₃V₅O₆₂H₂](abbreviated to P₂Mo₁₇V, P₂Mo₁₆V₂, P₂Mo₁₅V₃, P₂Mo₁₄V₄ and P₂Mo₁₃V₅, respectively), on the diphenolase activity of mushroom tyrosinase were investigated by enzyme kinetics methods. The results show that P₂Mo₁₇V, P₂Mo₁₆V₂ and P₂Mo₁₅V₃ have significant inhibitory effects on tyrosinase, and the half maximal inhibitory concentration(IC₅₀) values of them are 0.409, 0.386 and 0.386 mmol/L, respectively. They are reversible and competitive inhibitors, and the inhibition constants are 0.234, 0.391 and 0.249 mmol/L, respectively. P₂Mo₁₃V₅ can activate diphenolase activity of tyrosinase while P₂Mo₁₄V₄ in 0~1.0 mmol/L has no obvious effects on the diphenolase activity of tyrosinase.