Open AccessMutations at the C‐Terminal Isoleucine and Other Potential Iron Ligands of 5‐Lipoxygenase
Author(s) -
Hammarberg Tove,
Zhang YingYi,
Lind Birger,
Rådmark Olof,
Samuelsson Bengt
Publication year - 1995
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1995.0401h.x
Subject(s) - enzyme , lipoxygenase , biochemistry , escherichia coli , recombinant dna , ligand (biochemistry) , chemistry , heme , enzyme assay , microbiology and biotechnology , biology , receptor , gene
The non‐heme iron centre in human 5‐lipoxygenase was studied. Recombinant enzyme was expressed in Escherichia coli , purified and assayed for iron content and enzyme activity. For non‐mutated enzyme, the iron content was 1.01±0.19 mol/mol. Deletion of the C‐terminal Ile673 resulted in an iron content of 0.03±0.07 mol/mol and undetectable lipoxygenase activity. Mutations at His367, Glu376 and Asn554 led to drastically decreased enzyme activity (<2% of non‐mutated control) but iron was still present. In addition to Glu376, eight other conserved acidic residues (Asp/Glu) in 5‐lipoxygenase were replaced, none of which was crucial for enzyme activity. We conclude that Ile673 is an iron ligand in 5‐lipoxygenase, while our results do not support that Glu376 or Asn554 have this function. The possible role of His367 as a replaceable iron ligand is discussed.