A new quantitative approach to investigate the capability of iron heme complexes (HEM), metmyoglobin and hemin, to catalyze lipid peroxidation was elaborated. The oxidation of methyl linoleate in micellar solutions was used as a testing model. The key point was the determination of the rate of free radical generation, RIN, calculated from the rate of oxygen consumption. The HEM catalytic activity was characterized by two independent parameters: by reactivity and by its resistance to degradation. Both parameters were found to be pH-dependent. The reactivity was expressed as the effective rate constant for the reaction of HEM with lipid hydroperoxide. The resistance to degradation was characterized by the rate of the decrease in RIN with time and also by the regeneration coefficient, which shows how many active free radicals can be generated by one molecule of HEM. Both Hemin and metMB were found to be very effective catalysts even at nanomolar concentrations. The effective regeneration of active forms of HEM was observed. The catalytic activity of HEM was rapidly reduced with time. The kinetic scheme of the process under consideration was suggested, and this was applied for kinetic computer simulations.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jf0714362 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Ultrafast Relaxation Dynamics of Photoexcited Heme Model Compounds: Observation of Multiple Electronic Spin States and Vibrational Cooling.
J Phys Chem B
April 2017
Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019, Kerala India.
Hemin is a unique model compound of heme proteins carrying out variable biological functions. Here, the excited state relaxation dynamics of heme model compounds in the ferric form are systematically investigated by changing the axial ligand (Cl/Br), the peripheral substituent (vinyl/ethyl-meso), and the solvent (methanol/DMSO) using femtosecond pump-probe spectroscopy upon excitation at 380 nm. The relaxation time constants of these model compounds are obtained by global analysis.
View Article and Find Full Text PDFProtein electronic conductors: hemin-substrate bonding dictates transport mechanism and efficiency across myoglobin.
Angew Chem Int Ed Engl
October 2015
Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100 (Israel).
Electron transport (ETp) across met-myoglobin (m-Mb), as measured in a solid-state-like configuration between two electronic contacts, increases by up to 20 fold if Mb is covalently bound to one of the contacts, a Si electrode, in an oriented manner by its hemin (ferric) group, rather than in a non-oriented manner. Oriented binding of Mb is achieved by covalently binding hemin molecules to form a monolayer on the Si electrode, followed by reconstitution with apo-Mb. We found that the ETp temperature dependence (>120 K) of non-oriented m-Mb virtually disappears when bound in an oriented manner by the hemin group.
View Article and Find Full Text PDFComplexes of ferriheme nitrophorin 4 with low-molecular weight thiol(ate)s occurring in blood plasma.
J Inorg Biochem
May 2013
Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany.
Nitrophorins are proteins occurring in the saliva of the blood-sucking insect Rhodnius prolixus to carry NO as a vasodilator and blood-coagulation inhibitor into the victim's tissue. It was suggested that the rate of NO release can be enhanced by the blood-plasma component L-cysteine [J.M.
View Article and Find Full Text PDFRedox instability and hemin loss of mutant sperm whale myoglobins induced by 4-hydroxynonenal in vitro.
J Agric Food Chem
August 2012
Department of Animal Science, University of Connecticut, Storrs, Connecticut 06269, United States.
The effects of 4-hydroxy-2-nonenal (HNE) on redox stability of Oxy- and Deoxy- wild-type (WT) and recombinant sperm whale myoglobins (P88H/Q152H, L29F, H97A, and H64F) and hemin loss from Met-myoglobin (Mb) were investigated. HNE induced greater redox instability in WT and mutant Mbs compared to controls (p < 0.05).
View Article and Find Full Text PDFRole of heme in the unfolding and assembly of myoglobin.
Biochemistry
July 2010
Department of Biochemistry and Cell Biology and W. M. Keck Center for Computational Biology, Rice University, Houston, Texas 77005, USA.
The unfolding of wild-type holomyoglobin in the ferric state (metMb) appears to be a simple two-state process, even though hemichrome spectra are often observed and apoMb denaturation involves an intermediate. To resolve these discrepancies, we measured GuHCl-induced, equilibrium unfolding of five sperm whale metMb variants, which were selected to examine the relative importance of apoglobin stability and hemin affinity. Combined analysis of CD, Trp fluorescence, and Soret absorbance titration curves for all the variants requires a six-state mechanism containing native (N), intermediate (I), and unfolded (U) states of apoMb and their hemin-bound counterparts, NH (holoMb), IH, and UH, respectively.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!