Siverina O B, Basevich V V, Iaropolov A I
Biokhimiia. 1987 Feb;52(2):232-8.
The effect of pH on the kinetic parameters (Kms, Vs) of the reaction of adrenaline and Fe(II) (More's salt) oxidation by ceruloplasmin isolated from human donor blood was investigated. It was assumed that the imidazole group of histidine is functionally important for the above reactions. For Fe(II) the effect of the ionizeable group was observed during substrate binding to the ceruloplasmin molecule, whereas in the course of the adrenaline oxidation reaction it manifests itself during catalytic interaction of the substrate with the enzyme. The organic substrate can bind both to the protonated and to the non-protonated form of the enzyme. Fe(II) interacts only with the protonated form of the protein. In both cases, the rate-limiting step of the oxidase reaction is preceded by a single step, i.e., proton binding. The schemes describing the order of proton attachment in the course of the above reactions are proposed.
研究了pH对从人体供血者血液中分离的铜蓝蛋白氧化肾上腺素和Fe（II）（莫尔盐）反应动力学参数（Km、Vmax）的影响。据推测，组氨酸的咪唑基对上述反应具有重要功能。对于Fe（II），在底物与铜蓝蛋白分子结合过程中观察到可电离基团的影响，而在肾上腺素氧化反应过程中，它在底物与酶的催化相互作用中表现出来。有机底物可以与酶的质子化形式和非质子化形式结合。Fe（II）仅与蛋白质的质子化形式相互作用。在这两种情况下，氧化酶反应的限速步骤之前都有一个单一的步骤，即质子结合。提出了描述上述反应过程中质子附着顺序的方案。
