Appearance of the. nu. (Fe sup IV double bond O) vibration from a ferryl-oxo intermediate in the cytochrome oxidase/dioxygen reaction

Journal Article · Tue Aug 14 04:00:00 EDT 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00484a001· OSTI ID:6098333

Varotsis, C; Babcock, G T ^[1]

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1. Michigan State Univ., East Lansing (USA)

Time-resolved resonance Raman spectra have been recorded during the reaction of fully reduced (a{sup 2+}a{sub 3}{sup 2+}) cytochrome oxidase with dioxygen at room temperature. In the spectrum recorded at 800 {mu}s subsequent to carbon monoxide photolysis, a mode is observed at 790 cm{sup {minus}1} that shifts to 755 cm{sup {minus}1} when the experiment is repeated with {sup 18}O{sub 2}. The frequency of this vibration and the magnitude of the {sup 18}O{sub 2} isotopic frequency shift lead the authors to assign the 790-cm{sup {minus}1} mode to the Fe{sup IV}{double bond}O stretching vibration of a ferryl-oxo cytochrome a{sub 3} intermediate that occurs in the reaction of fully reduced cytochrome oxidase with dioxygen. The appearance and vibrational frequency of this mode were not affected when D{sub 2}O was used as a solvent. This result suggests that the ferryl-oxo intermediate is not hydrogen bonded. They have also recorded Raman spectra in the high-frequency region during the oxidase/O{sub 2} reaction that show that the oxidation of cytochrome a{sup 2+} is biphasic. These results on the kinetics of the redox activity of cytochrome a are consistent with the branched pathway discussed by Hill et al. for the oxidation of reduced cytochrome oxidase by O{sub 2} at room temperature.

• OSTI ID: 6098333
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:32; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
BIOCHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMICAL SHIFT
CYTOCHROME OXIDASE
ENERGY LEVELS
ENZYMES
EVEN-EVEN NUCLEI
EXCITED STATES
HAEM DEHYDROGENASES
HEAVY WATER
HYDROGEN COMPOUNDS
ISOTOPES
KINETICS
LASER SPECTROSCOPY
LIGHT NUCLEI
NUCLEI
OXIDATION
OXIDOREDUCTASES
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
RAMAN SPECTROSCOPY
REACTION INTERMEDIATES
REACTION KINETICS
SPECTROSCOPY
STABLE ISOTOPES
VIBRATIONAL STATES
WATER