Mutagenesis studies on the amino acid residues involved in the iron-binding and the activity of human 5-lipoxygenase.
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Ishii S, Noguchi M, Miyano M, Matsumoto T, Noma M
Mutagenesis studies on the amino acid residues involved in the iron-binding and the activity of human 5-lipoxygenase.
Biochem Biophys Res Commun. 1992 Feb 14;182(3):1482-90.
- PubMed ID
- 1540191 [ View in PubMed]
- Abstract
Human 5-lipoxygenase contains a non-heme iron essential for its activity. In order to determine which amino acid residues are involved in the iron-binding and the lipoxygenase activity, nine amino acid residues in highly homologous regions among the lipoxygenases were individually replaced by means of site-directed mutagenesis. Mutant 5-lipoxygenases in which His-367 or His-550 was replaced by either Asn or Ala, His-372 by either Asn or Ser, or Glu-376 by Gln were completely devoid of the activity. Though mutants containing an alanine residue instead of His-390 or His-399 lacked the activity, the corresponding asparagine substituted mutants exhibited. The other mutants retained the enzyme activity. These results strongly suggest that His-367, His-372, His-550 and Glu-376 are crucial for 5-lipoxygenase activity and coordinate to the essential iron.