The peroxidation of low density lipoprotein (LDL) may play an important role in the modification of the lipoprotein to an atherogenic form. The oxidation of LDL by peroxidases has recently been suggested as a model for in vivo transition metal ion-independent oxidation of LDL (Wieland, E., S. Parthasarathy, and D. Steinberg. 1993. Proc. Natl. Acad. Sci. USA. 90: 5929-5933). It is possible that in vivo the peroxidase activities of proteins, such as prostaglandin synthase and myeloperoxidase, promote LDL oxidation. We have used horseradish peroxidase (HRP) and H2O2 as a model of peroxidase-dependent oxidation of LDL and we observed the following during HRP/H2O2-initiated LDL oxidation. i) The oxidation of alpha-tocopherol occurred with the concomitant formation of alpha-tocopheroxyl radical. This was followed by the production of an apolipoprotein B (apoB)-derived radical. The apoB radical and the alpha-tocopheroxyl radical were formed under both aerobic and anaerobic conditions. ii) Inclusion of N-t-butyl-alpha-phenylnitrone (PBN) did not inhibit alpha-tocopheroxyl radical formation. The ESR spectrum of a PBN/LDL-lipid derived adduct was observed after prolonged incubation. iii) There was formation of conjugated dienes, lipid hydroperoxides and thiobarbituric acid reactive substances. Our data indicate that HRP/H2O2 oxidizes both alpha-tocopherol and apoB to the corresponding radicals and concomitantly initiates lipid peroxidation.
Download full-text PDF |
Source |
|---|
Publication Analysis
Top Keywords
Similar Publications
Selenium vitaminology: The connection between selenium, vitamin C, vitamin E, and ergothioneine.
Curr Opin Chem Biol
August 2023
Department of Biochemistry, 89 Beaumont Ave, Given Laboratory, Room B413, Burlington, VT, 05405, USA. Electronic address:
Selenium is connected to three small molecule antioxidant compounds, ascorbate, α-tocopherol, and ergothioneine. Ascorbate and α-tocopherol are true vitamins, while ergothioneine is a "vitamin-like" compound. Here we review how selenium is connected to all three.
View Article and Find Full Text PDFRapid Analysis of α-Tocopherol and Its Oxidation Products Using Supercritical Carbon Dioxide and Proton Transfer Reaction Ionization Mass Spectrometry.
Mass Spectrom (Tokyo)
December 2022
Forefront Research Center, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
We have developed a rapid and sensitive analytical method for α-tocopherol and its oxidative products by combining online hyphenation of supercritical fluid extraction-supercritical fluid chromatography (SFC) with proton transfer reaction (PTR) ionization mass spectrometry (MS). α-Tocopherol is a well-known antioxidant that plays a vital role in the antioxidant defense system in plant cells. However, studies on the cellular mechanisms of α-tocopherol have been limited owing to the lack of a rapid analytical method, which limits the comparison of plant cells incubated in various conditions.
View Article and Find Full Text PDFFormation of α-tocopherol hydroperoxide and α-tocopheroxyl radical: relevance for photooxidative stress in Arabidopsis.
Sci Rep
November 2020
Department of Biophysics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
Tocopherols, lipid-soluble antioxidants play a crucial role in the antioxidant defense system in higher plants. The antioxidant function of α-tocopherol has been widely studied; however, experimental data on the formation of its oxidation products is missing. In this study, we attempt to provide spectroscopic evidence on the detection of oxidation products of α-tocopherol formed by its interaction with singlet oxygen and lipid peroxyl radical.
View Article and Find Full Text PDFEffects of Environmental pH on Antioxidant Interactions between Rosmarinic Acid and α-Tocopherol in Oil-in-Water (O/W) Emulsions.
J Agric Food Chem
August 2016
Department of Food Science, Chenoweth Laboratory, University of Massachusetts, 100 Holdsworth Way, Amherst, Massachusetts 01003, United States.
Antioxidant regeneration could be influenced by various factors such as antioxidant locations and pH conditions. The effects of environmental pH on the antioxidant interaction between rosmarinic acid and α-tocopherol in oil-in-water (O/W) emulsions were investigated. Results showed that the combined antioxidants at pH 7 exhibited the strongest synergistic antioxidant activity in comparison with the combinations at other pH conditions as indicated by the interaction index.
View Article and Find Full Text PDFKinetic Study of Aroxyl-Radical-Scavenging and α-Tocopherol-Regeneration Rates of Five Catecholamines in Solution: Synergistic Effect of α-Tocopherol and Catecholamines.
J Phys Chem B
July 2016
Department of Chemistry, Faculty of Science, Ehime University, Matsuyama 790-8577, Japan.
Article Synopsis
- Detailed kinetic studies explored how various catecholamines (CAs) and catechins interact with aroxyl and α-tocopheroxyl radicals, focusing on their ability to scavenge free radicals.
- Rate constants for these reactions showed a hierarchy of effectiveness, with catecholamines like norepinephrine being the least effective and 6-hydroxydopamine and EGCG showing high scavenging activity, comparable to established antioxidants.
- The findings indicate that CAs can help protect against oxidative damage in the nervous system by neutralizing free radicals and aiding in the regeneration of α-tocopherol from its radical form.
Want 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!