Fujiwara T, Fukumori Y, Yamanaka T
Department of Life Science, Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Kanagawa.
J Biochem. 1992 Aug;112(2):290-8. doi: 10.1093/oxfordjournals.jbchem.a123893.
A novel type of cytochrome c oxidase was purified to homogeneity from Pseudomonas aeruginosa which was grown aerobically. The purified oxidase contained two molecules of heme a, two atoms of copper, and one molecule of protoheme per molecule. One of the two heme a molecules in the oxidase reacted with carbon monoxide, so that the enzyme was of baa3-type. The oxidase molecule was composed of three subunits with molecular weights of 38,000, 57,000, and 82,000. Although the oxidase oxidized ferrocytochrome c-550 obtained from the bacterial cells grown aerobically, the oxidizing activity was not high. The "resting form" and the "pulsed form" of the oxidase were observed clearly with this enzyme, and the transition from the resting form to the pulsed form was accompanied by a distinct change of the enzymatic activity. The difference in the kinetics of the catalytic reactions between the two forms is discussed.
从需氧生长的铜绿假单胞菌中纯化出一种新型细胞色素c氧化酶，并使其达到同质。纯化后的氧化酶每分子含有两个血红素a分子、两个铜原子和一个原血红素分子。氧化酶中的两个血红素a分子之一可与一氧化碳反应，因此该酶属于baa3型。氧化酶分子由三个亚基组成，分子量分别为38,000、57,000和82,000。尽管该氧化酶可氧化从需氧生长的细菌细胞中获得的亚铁细胞色素c-550，但其氧化活性并不高。用这种酶可清楚地观察到氧化酶的“静止形式”和“脉冲形式”，并且从静止形式到脉冲形式的转变伴随着酶活性的明显变化。文中讨论了两种形式催化反应动力学的差异。
