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Observation of the O-O Stretching Resonance Raman Band for Cytochrome P-450cam Under Catalytic Conditions

  • T. Egawa
  • T. Ogura
  • R. Makino
  • Y. Ishimura
  • T. Kitagawa
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 68)

Abstract

Cytochrome P-450 (P-450) is a generic name of heme proteins which have the catalytic activity for monooxygenation of a variety of organic compounds. In their catalytic reaction one oxygen atom of the heme-bound dioxygen is incorporated into a substrate while the other oxygen atom is converted into water. The question to be answered is whether the dioxygen bound to P-450 differs from those of other heme proteins. The O-O stretching (v OO) frequency is expected to reflect most sensitively the nature of the O-O bond. Bangcharoenpaurpong et al. [1] succeeded in observing the v OO RR band for noncatalytic O2 adduct of frozen P-450cam with no electron donor present at -6° C and it was recently confirmed for a solution at -20° C by Nishimura et al. [2]. The observed v OO frequency was, unexpectedly, very close to that of oxy-myoglobin (oxyMb) in which the heme bound dioxygen is nonreactive. We thought it important to detect the v OO RR band for oxy P-450cam under catalytic conditions, that is, at room temperature in the presence of electron donor (reduced putidaredoxin; Pdr) and substrate (D-camphor). Since the reaction becomes faster under such conditions (It is reported that Pdr and P-450cam is associate to form a bimolecular complex and the life time of oxy P-450 m is made significantly shorter by formation of the complex [3]), it is hard to detect oxy P-450cam with an ordinary technique. Accordingly, we applied a home made mixed-flow transient Raman apparatus to observe the v OO RR band successfully.

Keywords

Electron Donor Isotopic Shift Vibrational Spectroscopy Heme Protein Visible Absorption Spectrum 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

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    O. Bangcharoenpaurpong, A. K. Rizos, P. M. Champion, D. Jollie, and S. G. Sligar, J. Biol. Chem. 261, 8089 (1986).Google Scholar
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    Y. Nishimura, R. Makino, M. Imai, H. Shimada, H. Koga, T. Horiuchi, and Y. Ishimura, Proc. Xllth Intl. Conf. Raman Spectrosc. (J. R. Durig, and J. F. Sullivan Eds.), pp. 702, John Wiley, (1990).Google Scholar
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Copyright information

© Springer-Verlag Berlin Heidelberg 1992

Authors and Affiliations

  • T. Egawa
    • 1
  • T. Ogura
    • 1
  • R. Makino
    • 2
  • Y. Ishimura
    • 2
  • T. Kitagawa
    • 1
  1. 1.Institute for Molecular ScienceOkazaki 444Japan
  2. 2.Keio UniversityShijuku-ku, Tokyo 160Japan

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