Observation of the FeIV=O stretching Raman band for a thiolate‐ligated heme protein Compound I of chloroperoxidase

FEBS Letters

Ishimura, Yuzuru²  Makino, Ryu²  Ogura, Takashi¹  Egawa, Tsuyoshi¹  Miki, Hideho²  Kitagawa, Teizo¹ 

[1] Institute for Molecular Science, Okazaki National Research Institutes, Myodaiji, Okazaki 444, Japan;Department of Biochemistry, School of Medicine, Kelo University, Shinjuku-ku, Tokyo 160, Japan

关键词: Chloroperoxidase;    Compound I;    Compound II;    Ferryl-oxo stretching mode;    Resonance Raman;    Thiolate-ligated heme;   

DOI  :  10.1016/0014-5793(92)80668-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The Fe^IV=O stretching vibration has never been identified for a cysteine-coordinated heme enzyme. In this study, resonance Raman and visible absorption spectra were observed simultaneously for transient species in the catalytic reaction of chloroperoxidase with hydrogen peroxide by using our original apparatus for mixed-flow and Raman/absorption simultaneous measurements. For the first intermediate, the Fe^IV=O stretching Raman band was observed at 790 cm⁻¹, which shifted to 756 cm⁻¹ with the ¹⁸O derivative, but the ν₄ band was too weak to be identified. This suggested the formation of an oxoferryl porphyrin π cation radical. The second intermediate gave an intense ν₄ band at 1,372 cm⁻¹ but no oxygen isotope-sensitive Raman band, suggesting oxygen exchange with bulk water.

【 授权许可】

Unknown