Jiménez M, García-Cánovas F, García-Carmona F, Iborra J L, Lozano J A
Biochem Int. 1985 Jul;11(1):51-9.
The present work deals with isoproterenol oxidation by mushroom tyrosinase and sodium metaperiodate. Intermediates produced at short reaction time were characterized by scanning repetitive spectrophotometry and the stoichiometry of the respective aminochrome appearance was established. The oxidation pathway from isoproterenol to aminochrome is parallel to the previously proposed for L-dopa oxidation by mushroom tyrosinase, whose steps are as follow: Isoproterenol----o-quinone-H+----o-quinone----leukoaminochrome---- aminochrome. The stoichiometry for the conversion of o-quinone-H+ into the aminochrome of isoproterenol followed the equation: 2 o-quinone-H+----isoproterenol + aminochrome. The kinetics of chemical reactions that take place from the o-quinone-H+ to aminochrome has been studied as a system of various chemical reactions coupled to an enzymatic reaction (EzCC: Enzymatic-Chemical-Chemical mechanism).
本研究涉及蘑菇酪氨酸酶和偏高碘酸钠对异丙肾上腺素的氧化作用。通过扫描重复分光光度法对短反应时间产生的中间体进行了表征，并确定了相应氨基色素出现的化学计量关系。从异丙肾上腺素到氨基色素的氧化途径与先前提出的蘑菇酪氨酸酶氧化L-多巴的途径平行，其步骤如下：异丙肾上腺素→邻醌-H⁺→邻醌→无色氨基色素→氨基色素。邻醌-H⁺转化为异丙肾上腺素氨基色素的化学计量关系遵循以下方程式：2邻醌-H⁺→异丙肾上腺素+氨基色素。从邻醌-H⁺到氨基色素发生的化学反应动力学已作为一个与酶促反应耦合的各种化学反应系统（EzCC：酶促-化学-化学机制）进行了研究。
