Probing the oxygen activation reaction in intact whole mitochondria through analysis of molecular vibrations.
The process of dioxygen reduction catalyzed by cytochrome c oxidase was investigated by examining intact porcine mitochondrial preparations using a novel time-resolved resonance Raman measurement system at experimental accuracy levels equivalent to those of the reaction system of the solubilized and purified enzyme. The resonance Raman bands assignable to the initial three intermediates were detected at frequencies identical to those observed with purified enzyme preparations. However, the lifetime of the initial intermediate (the oxygenated species) in the mitochondrial preparation was found to be significantly longer than that observed in purified preparations, suggesting that control of the stability of the oxygenated species is imposed by the mitochondrial membrane system.
Takahashi
Toshinari
T
Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan.
Kuroiwa
Shigeki
S
Ogura
Takashi
T
Yoshikawa
Shinya
S
D000818:Animals; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000378:metabolism; D008929:Mitochondria, Heart / Q000737:chemistry* / Q000201:enzymology / Q000378:metabolism; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry* / Q000378:metabolism; D010103:Oxygen Isotopes / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D013552:Swine
D010103:Oxygen Isotopes; D003576:Electron Transport Complex IV; D010100:Oxygen