Effects of the arrangement of a distal catalytic residue on regioselectivity and reactivity in the coupled oxidation of sperm whale myoglobin mutants

Tatsuya Murakami, Isao Morishima, Toshitaka Matsui, Shin Ichi Ozaki, Isao Hara, Hui Jun Yang, Yoshihito Watanabe

研究成果: Article

21 引用 (Scopus)

抜粋

The coupled oxidations of sperm whale myoglobin (Mb) mutants are performed to examine active site residues controlling the regiospecific heme degradation. HPLC analysis of biliverdin isomers shows that L29H/H64L Mb almost exclusively gives biliverdin IXγ, although H64L and wild-type Mb mainly afford the α-isomer. Relocation of the distal histidine at the 43 and 107 positions increases the amount of γ-isomer to 44 and 22%, respectively. Interestingly, the increase in the ratio of γ-isomer is also observed by a single replacement of either His-64 with Asp or Phe-43 with Trp. It appears that the polarity of the active site as well as hydrogen bonding between oxygen molecule bound to the heme iron and His or Trp is important in controlling the regioselectivity. The results of coupled oxidation kinetics, autoxidation kinetics, and redox potential of the Fe3+/Fe2+ couple are discussed with regard to their implications for the active site and mechanism of heme oxygenase.

元の言語English
ページ(範囲)2007-2011
ページ数5
ジャーナルJournal of the American Chemical Society
121
発行部数10
DOI
出版物ステータスPublished - 1999 3 17
外部発表Yes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

フィンガープリント Effects of the arrangement of a distal catalytic residue on regioselectivity and reactivity in the coupled oxidation of sperm whale myoglobin mutants' の研究トピックを掘り下げます。これらはともに一意のフィンガープリントを構成します。

  • これを引用