Importance of histidine residue 25 of rat heme oxygenase for its catalytic activity.
A truncated, soluble, and enzymatically active rat heme oxygenase lacking its membrane-associative, C-terminal segment was expressed in E. coli strain JM109. The roles of its four histidine residues were examined by determining the enzymatic activities of mutant enzymes in which each of these residues in turn was replaced by alanine. Mutation of histidine residue 25 to alanine resulted in marked decrease in activity for heme breakdown, indicating that this histidine residue has an important role in the heme oxygenase reaction.
Ishikawa
K
K
Department of Biochemistry, Yamagata University School of Medicine, Japan.
Sato
M
M
Ito
M
M
Yoshida
T
T
D000409:Alanine; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics / Q000378:metabolism*; D006639:Histidine; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010446:Peptide Fragments / Q000378:metabolism; D016133:Polymerase Chain Reaction; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D013053:Spectrophotometry
D009838:Oligodeoxyribonucleotides; D010446:Peptide Fragments; D011994:Recombinant Proteins; D006639:Histidine; D006419:Heme Oxygenase (Decyclizing); D000409:Alanine