title: Cytochrome c oxidase from Paracoccus denitrificans in Triton X-100: aggregation state and kinetics.
abstract: Cytochrome c oxidase from Paracoccus denitrificans was homogeneously dispersed in Triton X-100. Using gel exclusion chromatography and sucrose gradient centrifugation analysis a molecular weight of the detergent-protein complex of 155,000 was determined. After subtraction of the bound detergent (111 mol/mol heme aa3) a molecular weight of 85,000 resulted, which agreed well with the model of a monomer containing two subunits. This monomer showed high cytochrome c oxidase activity when measured spectrophotometrically in the presence of Triton X-100 (Vmax = 85 s-1). The molecular activity, plotted according to Eadie-Hofstee, was monophasic as a function of the cytochrome c concentration. A Km of 3.6 X 10(-6) M was evaluated, similar to the Km observed in the presence of dodecyl maltoside [Nałecz et al. (1985).
mesh_terms: D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000302:isolation & purification* / Q000378:metabolism; D007700:Kinetics; D008970:Molecular Weight; D017830:Octoxynol; D010231:Paracoccus denitrificans / Q000201:enzymology*; D011092:Polyethylene Glycols; D011487:Protein Conformation
chemical_list: D011092:Polyethylene Glycols; D017830:Octoxynol; D003576:Electron Transport Complex IV