title: Mass spectrometric identification of lysine residues of heme oxygenase-1 that are involved in its interaction with NADPH-cytochrome P450 reductase.
abstract: The lysine residues of rat heme oxygenase-1 (HO-1) were acetylated by acetic anhydride in the absence and presence of NADPH-cytochrome P450 reductase (CPR) or biliverdin reductase (BVR). Nine acetylated peptides were identified by MALDI-TOF mass spectrometry in the tryptic fragments obtained from HO-1 acetylated without the reductases (referred to as the fully acetylated HO-1). The presence of CPR prevented HO-1 from acetylation of lysine residues, Lys-149 and Lys-153, located in the F-helix. The heme degradation activity of the fully acetylated HO-1 in the NADPH/CPR-supported system was significantly reduced, whereas almost no inactivation was detected in HO-1 in the presence of CPR, which prevented acetylation of Lys-149 and Lys-153. On the other hand, the presence of BVR showed no protective effect on the acetylation of HO-1. The interaction of HO-1 with CPR or BVR is discussed based on the acetylation pattern and on molecular modeling.
authors.affiliation: Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Higashimoto
authors.forename: Masakazu
authors.initials: M
authors.lastname: Sugishima
authors.forename: Hideaki
authors.initials: H
authors.lastname: Sato
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakamoto
authors.forename: Keiichi
authors.initials: K
authors.lastname: Fukuyama
authors.forename: Graham
authors.initials: G
authors.lastname: Palmer
authors.forename: Masato
authors.initials: M
authors.lastname: Noguchi
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D003198:Computer Simulation; D004789:Enzyme Activation; D006419:Heme Oxygenase (Decyclizing) / Q000737:chemistry* / Q000648:ultrastructure*; D008239:Lysine / Q000737:chemistry*; D013058:Mass Spectrometry; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009251:NADPH-Ferrihemoprotein Reductase / Q000737:chemistry* / Q000648:ultrastructure*; D010449:Peptide Mapping; D011485:Protein Binding; D025941:Protein Interaction Mapping
chemical_list: D006419:Heme Oxygenase (Decyclizing); C491523:Hmox1 protein, rat; D009251:NADPH-Ferrihemoprotein Reductase; D008239:Lysine