PSEUDOPEROXIDASE INVESTIGATIONS OF HYDROPEROXIDES AND INHIBITORS WITH HUMAN LIPOXYGENASES

Autor: Theodore R. Holman, Eric K. Hoobler, Charles Holz
Jazyk: angličtina
Rok vydání: 2013
Předmět:
endocrine system diseases
Clinical Biochemistry
Cell
Lipoxygenase
Pharmaceutical Science
01 natural sciences
Biochemistry
chemistry.chemical_compound
Drug Discovery
Lipoxygenase Inhibitors
Hydrogen peroxide
Medicine(all)
0303 health sciences
biology
integumentary system
food and beverages
Lipoxygenases
3. Good health
Hydroperoxide
medicine.anatomical_structure
Linoleic Acids
Sulfoxides
Molecular Medicine
lipids (amino acids
peptides
and proteins)
Oxidation-Reduction
Peroxidase
musculoskeletal diseases
Lipid Peroxides
Inhibitor
Isozyme
Article
03 medical and health sciences
Phenols
medicine
Humans
Molecular Biology
030304 developmental biology
Enzyme Assays
010405 organic chemistry
Organic Chemistry
Hydrogen Peroxide
Ascorbic acid
Enzyme assay
0104 chemical sciences
Nordihydroguaiaretic acid
chemistry
biology.protein
Pseudoperoxidase
Popis: Understanding the mode of action for lipoxygenase (LOX) inhibitors is critical to determining their efficacy in the cell. The pseudoperoxidase assay is an important tool for establishing if a LOX inhibitor is reductive in nature, however, there have been difficulties identifying the proper conditions for each of the many human LOX isozymes. In the current paper, both the 234nM decomposition (UV) and iron-xylenol orange (XO) assays are shown to be effective methods of detecting pseudoperoxidase activity for 5-LOX, 12-LOX, 15-LOX-1 and 15-LOX-2, but only if 13-(S)-HPODE is used as the hydroperoxide substrate. The AA products, 12-(S)-HPETE and 15-(S)-HPETE, are not consistent hydroperoxide substrates since they undergo a competing transformation to the di-HETE products. Utilizing the above conditions, the selective 12-LOX and 15-LOX-1 inhibitors, probes for diabetes, stroke and asthma, are characterized for their inhibitory nature. Interestingly, ascorbic acid also supports the pseudoperoxidase assay, suggesting that it may have a role in maintaining the inactive ferrous form of LOX in the cell. In addition, it is observed that nordihydroguaiaretic acid (NDGA), a known reductive LOX inhibitor, appears to generate radical species during the pseudoperoxidase assay, which are potent inhibitors against the human LOX isozymes, producing a negative pseudoperoxidase result. Therefore, inhibitors that do not support the pseudoperoxidase assay with the human LOX isozymes, should also be investigated for rapid inactivation, to clarify the negative pseudoperoxidase result.
Databáze: OpenAIRE
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