title: active site modifications of the brain isoform of creatine kinase by 4-hydroxy-2-nonenal correlate with reduced enzyme activity: mapping of modified sites by Fourier transform-ion cyclotron resonance mass spectrometry.
abstract: Creatine kinase reversibly catalyzes the transfer of the high-energy phosphoryl group from phosphocreatine to MgADP for rapid regeneration of ATP. It is hypothesized that factors which perturb creatine kinase activity, such as reactive oxygen species resulting from oxidative stress, could have a major role in the pathogenesis of diseases, particularly in the brain, where the level of ATP utilization is high. The reactive aldehyde 4-hydroxy-2-nonenal is a major secondary product of lipid peroxidation caused by oxidative stress; the levels of both free and protein-bound 4-hydroxy-2-nonenal are increased in Alzheimer's disease brain. Preliminary reports indicated that creatine kinase had lower activity in Alzheimer's disease brain. In this study, we investigated the structural and functional consequences of reacting the cytosolic brain isoform of creatine kinase with 4-hydroxy-2-nonenal at pathophysiologically relevant concentrations of 4-hydroxy-2-nonenal (10-300 microM). Dose-dependent reduction of enzyme activity was observed and, for the first time, correlated with 4-hydroxy-2-nonenal adduct formation on specific amino acid residues, including the active site residues His66, His191, Cys283, and His296 as determined by Fourier transform-ion cyclotron resonance mass spectrometry.
authors: Department of Pharmacology-Toxicology, UAB Biomedical FT-ICR MS Laboratory, University of Alabama at Birmingham, 1918 University Boulevard, Birmingham, LA 35294, USA.
authors: Shannon M
authors: SM
authors: Eliuk
authors: Matthew B
authors: MB
authors: Renfrow
authors: Erin M
authors: EM
authors: Shonsey
authors: Stephen
authors: S
authors: Barnes
authors: Helen
authors: H
authors: Kim
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000595:Amino Acid Sequence; D001665:Binding Sites; D001921:Brain / Q000201:enzymology*; D002853:Chromatography, Liquid; D003402:Creatine Kinase / Q000737:chemistry*; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000737:chemistry; D005583:Fourier Analysis; D006801:Humans; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D020033:Protein Isoforms / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000447:Aldehydes; D004791:Enzyme Inhibitors; D020033:Protein Isoforms; D003402:Creatine Kinase; C027576:4-hydroxy-2-nonenal