The cytochrome cbo from the obligate methylotroph Methylobacillus flagellatus KT is a cytochrome c oxidaseстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:The cbo-type oxidase of Methylobacillus flagellatus KT was purified to homogeneity by preparative native gel electrophoresis, and the kinetic properties and substrate specificity of the enzyme were studied. Ascorbate and ascorbate/N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) were oxidized by cytochrome cbo with a pH optimum of 8.3. With TMPD as an electron donor for the cbo-type oxidase, the optimal pH (7.0 to 7.6) was determined from the difference between respiration rates in the presence of ascorbate/TMPD and only ascorbate. The kinetic constants determined at pH 7.0 were as follows: oxidation by the enzyme of reduced TMPD was characterized by K-M = 0.86 mM and V-max = 1.1 mumol O-2/(min mg protein), and oxidation of reduced horse heart cytochrome c was characterized by K-M = 0.09 mM and V-max = 0.9 mumol O-2/(min mg protein). Cyanide inhibited ascorbate/TMPD-oxidase activity (K-i = 4.5-5.0 muM). The soluble cytochrome c(H) (12 kDa), partially purified from M. flagellatus KT, was found to serve as a natural electron donor for the cbo-type oxidase.