Biochemical and electrochemical characterization of quinohemoprotein amine dehydrogenase from Paracoccus denitrificans.
Biochemical and electrochemical characterization of quinohemoprotein amine dehydrogenase from Paracoccus denitrificans.
复制标题
脱氮副球菌的醌血红素蛋白胺脱氢酶的生化和电化学表征。
DOI：
10.1021/bi9828268
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发表时间：
1999
期刊：
影响因子：
2.9
通讯作者：
T. Ikeda
中科院分区：
文献类型：
--
作者：
K. Takagi;M. Torimura;Katsunori Kawaguchi;K. Kano;T. Ikeda
从反硝化副球菌IFO 12442中分离到一种新的喹诺血红蛋白胺脱氢酶，并对其进行了生化和电化学表征。该酶存在于周质中，催化初级脂肪胺和芳香胺的氧化脱胺作用。正丁胺或苄胺作为碳源和能量源强烈诱导酶的表达。羰基试剂不可逆地抑制酶活性。该酶是由α和β亚基组成的异源二聚体，分子量分别为59.5和36.5 kDa。紫外可见光谱和EPR光谱以及SDS-PAGE谱带的醌依赖氧化还原循环和血红素依赖过氧化染色显示，α亚基每个分子含有一个醌类辅助因子和一个血红素c，而β亚基没有假基。用介质辅助连续流柱电解光谱电化学技术测定了血红素c在pH 7.0条件下的氧化还原电位为0.192 V vs NHE。通过对底物滴定曲线的分析，估计醌/半醌和半醌/喹啉的氧化还原电位分别为0.19 V和0.11 V。
A new quinohemoprotein amine dehydrogenase from Paracoccus denitrificans IFO 12442 was isolated and characterized in views of biochemistry and electrochemistry. This enzyme exists in periplasm and catalyzes the oxidative deamination of primary aliphatic and aromatic amines. n-Butylamine or benzylamine as a carbon and energy source strongly induces the expression of the enzyme. Carbonyl reagents inhibit the enzyme activity irreversibly. This enzyme is a heterodimer constituted of alpha and beta subunits with the molecular mass of 59.5 and 36.5 kDa, respectively. UV-vis and EPR spectroscopy, and the quinone-dependent redox cycling and heme-dependent peroxidative stains of SDS-PAGE bands revealed that the alpha subunit contains one quinonoid cofactor and one heme c per molecule, while the beta subunit has no prosthetic group. The redox potential of the heme c moiety was determined to be 0.192 V vs NHE at pH 7.0 by a mediator-assisted continuous-flow column electrolytic spectroelectrochemical technique. The analysis of the substrate titration curve allowed the evaluation of the redox potential of the quinone/semiquinone and semiquinone/quinol redox couples as 0.19 and 0.11 V, respectively.