Journal article
Antioxidant-Mediated Modulation of Protein Reactivity for 3,4-Dihydroxyphenylacetaldehyde, a Toxic Dopamine Metabolite
Chemical research in toxicology, Vol.29(7), pp.1098-1107
07/18/2016
DOI: 10.1021/acs.chemrestox.5b00528
PMCID: PMC5248556
PMID: 27268734
Abstract
3,4-Dihydroxyphenylacetaldehyde (DOPAL) is an endogenously produced toxic aldehyde. It is a bifunctional electrophile implicated in the loss of dopaminergic cells concomitant with Parkinson’s disease and neurodegeneration. DOPAL is known to react with proteins and amino acids such as N-acetyl Lys; oxidation of the catechol moiety to the quinone of DOPAL increases this reactivity. Here we demonstrate the ability of the antioxidants N-acetylcysteine, glutathione, and ascorbic acid to mitigate the reactivity of DOPAL with proteins and amino acids in a dose-dependent fashion. Conversely, Trolox did not lessen the observed reactivity with proteins. Interestingly, use of tricine, a buffer and reducing agent, in these systems also decreased the reactivity of DOPAL with amines, yielding tricine-derived free radical species. Modification of amines with aldehydes typically involves Schiff base chemistry; however, the observance of free radicals suggests that an oxidative step is involved in the reaction of DOPAL with lysine. Furthermore, while Schiff base formation is usually optimal at pH 5, the reaction rate of DOPAL with N-acetyl Lys is negligible at pH 5 and is enhanced under basic conditions (
e.g
. pH 9). Conditions of high pH are also favorable for catechol auto-oxidation, known to occur for DOPAL. The antioxidant-mediated protection demonstrated here suggests that oxidative stress may impart cellular vulnerability to protein modification by DOPAL. Therefore, depleted antioxidants and increased levels of lipid peroxidation products, known to prevent detoxifying metabolism of DOPAL, may present a survival challenge to dopaminergic cells targeted in Parkinson’s disease.
Details
- Title: Subtitle
- Antioxidant-Mediated Modulation of Protein Reactivity for 3,4-Dihydroxyphenylacetaldehyde, a Toxic Dopamine Metabolite
- Creators
- David G Anderson - Department of Pharmaceutical Sciences and Experimental Therapeutics, Division of Medicinal and Natural Products Chemistry, College of Pharmacy, The University of Iowa 115 South Grand Ave, Iowa City, Iowa 52242-1112Virginia R Florang - Department of Pharmaceutical Sciences and Experimental Therapeutics, Division of Medicinal and Natural Products Chemistry, College of Pharmacy, The University of Iowa 115 South Grand Ave, Iowa City, Iowa 52242-1112Josephine H Schamp - Department of Pharmaceutical Sciences and Experimental Therapeutics, Division of Medicinal and Natural Products Chemistry, College of Pharmacy, The University of Iowa 115 South Grand Ave, Iowa City, Iowa 52242-1112Garry R Buettner - Free Radical and Radiation Biology Program, ESR Facility, Department of Radiation Oncology, College of Medicine, University of Iowa, Iowa City, Iowa 52242-1101Jonathan A Doorn - Department of Pharmaceutical Sciences and Experimental Therapeutics, Division of Medicinal and Natural Products Chemistry, College of Pharmacy, The University of Iowa 115 South Grand Ave, Iowa City, Iowa 52242-1112
- Resource Type
- Journal article
- Publication Details
- Chemical research in toxicology, Vol.29(7), pp.1098-1107
- DOI
- 10.1021/acs.chemrestox.5b00528
- PMID
- 27268734
- PMCID
- PMC5248556
- NLM abbreviation
- Chem Res Toxicol
- ISSN
- 0893-228X
- eISSN
- 1520-5010
- Grant note
- DOI: 10.13039/100000066, name: National Institute of Environmental Health Sciences, award: P42 ES013661, R01 ES015507; DOI: 10.13039/100000054, name: National Cancer Institute, award: P30 CA086862, R01 CA169046
- Language
- English
- Date published
- 07/18/2016
- Academic Unit
- Neurology; Iowa Neuroscience Institute; Pharmaceutical Sciences and Experimental Therapeutics; Radiation Oncology; Iowa Superfund Research Program; Medicinal and Natural Products Chemistry
- Record Identifier
- 9984047638502771
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