Carbon monoxide complex of cytochrome b(5) at acidic pH.
CO complex of cyt b(5) generated at acidic pH is investigated by absorption, resonance Raman (RR), and far UV CD measurements. The Soret maximum wavelength blue-shifted to 420 nm with other absorption bands observed around 540 and 570 nm for reduced cyt b(5) upon interaction with CO at acidic pH (pH 3.1-3.5). Under this condition, the iron-carbon stretching RR band was observed at 529 cm(-1) (520 cm(-1) for C(18)O), which indicated formation of a heme&bond;CO adduct with a histidine as an axial ligand. Heme dissociated from the reduced cyt b(5) protein at pH approximately 3.5, whereas its rate decreased under CO atmosphere compared with N(2) atmosphere, due to formation of a heme&bond;CO adduct with a histidine as an axial ligand.
Department of Chemistry, Research Center for Materials Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan. k4623a@nucc.cc.nagoya-u.ac.jp
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Hirota
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Kishi
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Yamauchi
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Wang
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Huang
D002248:Carbon Monoxide / Q000378:metabolism*; D002942:Circular Dichroism; D015786:Cytochromes b5 / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D011485:Protein Binding; D013059:Spectrum Analysis, Raman
D002248:Carbon Monoxide; D015786:Cytochromes b5