Cabanes J, García-Carmona F, García-Cánovas F, Iborra J L, Lozano J A
Biochim Biophys Acta. 1984 Oct 23;790(2):101-7. doi: 10.1016/0167-4838(84)90212-7.
The inhibition by m-coumaric acid of oxidation of L-dopa by epidermis tyrosinase (monophenol,dihydroxy-L-phenylalanine:oxygen oxidoreductase, EC 1.14.18.1) is characterized by a prolonged transient phase. Kinetic data correspond to that for a postulated mechanism that involves rapid formation of a reduced enzyme-m-coumaric acid complex that subsequently undergoes a relatively slow reversible reaction. An overall inhibition constant for m-coumaric acid of 0.05 mM was calculated. The value of the Ki for the dissociation of m-coumaric acid from the rapidly formed complex was calculated as 0.53 mM. The first-order rate constants for the slow isomerization of the enzyme-inhibitor complex were calculated as 3.0 +/- 0.1 min-1 for the forward step and 0.31 +/- 0.06 min-1 for the reverse step.
间香豆酸对表皮酪氨酸酶（单酚，二羟基-L-苯丙氨酸：氧氧化还原酶，EC 1.14.18.1）催化L-多巴氧化的抑制作用具有一个延长的瞬态阶段。动力学数据与一种假定机制相符，该机制涉及快速形成还原型酶-间香豆酸复合物，随后该复合物经历相对缓慢的可逆反应。计算出间香豆酸的总体抑制常数为0.05 mM。间香豆酸从快速形成的复合物中解离的Ki值计算为0.53 mM。酶-抑制剂复合物缓慢异构化的一级速率常数，正向步骤计算为3.0±0.1 min⁻¹，反向步骤计算为0.31±0.06 min⁻¹。
