scholarly journals The protein oxidation product 3,4-dihydroxyphenylalanine (DOPA) mediates oxidative DNA damage

1998 ◽  
Vol 330 (3) ◽  
pp. 1059-1067 ◽  
Author(s):  
Bénédicte MORIN ◽  
J. Michael DAVIES ◽  
T. Roger DEAN
Keyword(s):  
Protein Oxidation ◽  
Oxidative Dna Damage ◽  
Transition Metal Ions ◽  
Gradient Elution ◽  
Major Product ◽  
Oxidation Products ◽  
Single Experiment ◽  
Virtual Absence ◽  
Calf Thymus ◽  
Dopa Concentration

A major product of hydroxy-radical addition to tyrosine is 3,4-dihydroxyphenylalanine (DOPA) which has reducing properties. Protein-bound DOPA (PB-DOPA) has been shown to be a major component of the stable reducing species formed during protein oxidation under several conditions. The aim of the present work was to investigate whether DOPA, and especially PB-DOPA, can mediate oxidative damage to DNA. We chose to generate PB-DOPA using mushroom tyrosinase, which catalyses the hydroxylation of tyrosine residues in protein. This permitted us to study the reactions of PB-DOPA in the virtual absence of other protein-bound oxidation products. The formation of two oxidation products of DNA, 8-oxo-7,8-dihydro-2ʹ-deoxyguanosine (8oxodG) and 5-hydroxy-2ʹ-deoxycytidine (5OHdC), were studied with a novel HPLC using gradient elution and an electrochemical detection method, which allowed the detection of both DNA modifications in a single experiment. We found that exposure of calf thymus DNA to DOPA or PB-DOPA resulted in the formation of 8oxodG and 5OHdC, with the former predominating. The formation of these DNA oxidation products by either DOPA or PB-DOPA depended on the presence of oxygen, and also on the presence and on the concentration of transition metal ions, with copper being more effective than iron. The yields of 8oxodG and 5OHdC increased with DOPA concentration in proteins. Thus PB-DOPA was able to promote further radical-generating events, which then transferred damage to other biomolecules such as DNA.

scholarly journals Measurement of oxidative DNA damage by gas chromatography–mass spectrometry: ethanethiol prevents artifactual generation of oxidized DNA bases

1998 ◽  
Vol 331 (2) ◽  
pp. 365-369 ◽  
Author(s):  
Andrew JENNER ◽  
Timothy G. ENGLAND ◽  
Okezie I. ARUOMA ◽  
Barry HALLIWELL
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Oxidative Dna Damage ◽  
Oxidation Products ◽  
Dna Bases ◽  
Calf Thymus Dna ◽  
Gas Chromatography Mass Spectrometry ◽  
Calf Thymus ◽  
Oxidative Damage To Dna ◽  
Derivatization Reaction

Analysis of oxidative damage to DNA bases by GC-MS enables identification of a range of base oxidation products, but requires a derivatization procedure. However, derivatization at high temperature in the presence of air can cause ‘artifactual ’ oxidation of some undamaged bases, leading to an overestimation of their oxidation products, including 8-hydroxyguanine. Therefore derivatization conditions that could minimize this problem were investigated. Decreasing derivatization temperature to 23 °C lowered levels of 8-hydroxyguanine, 8-hydroxyadenine, 5-hydroxycytosine and 5-(hydroxymethyl)uracil measured by GC–MS in hydrolysed calf thymus DNA. Addition of the reducing agent ethanethiol (5%, v/v) to DNA samples during trimethylsilylation at 90 °C also decreased levels of these four oxidized DNA bases as well as 5-hydroxyuracil. Removal of guanine from hydrolysed DNA samples by treatment with guanase, prior to derivatization, resulted in 8-hydroxyguanine levels (54–59 pmol/mg of DNA) that were significantly lower than samples not pretreated with guanase, independent of the derivatizationconditions used. Only hydrolysed DNA samples that were derivatized at 23 °C in the presence of ethanethiol produced 8-hydroxyguanine levels (56±8 pmol/mg of DNA) that were as low as those of guanase-pretreated samples. Levels of other oxidized bases were similar to samples derivatized at 23 °C without ethanethiol, except for 5-hydroxycytosine and 5-hydroxyuracil, which were further decreased by ethanethiol. Levels of 8-hydroxyguanine, 8-hydroxyadenine and 5-hydroxycytosine measured in hydrolysed calf thymus DNA by the improved procedures described here were comparable with those reported previously by HPLC with electrochemical detection and by GC–MS with prepurification to remove undamaged base. We conclude that artifactual oxidation of DNA bases during derivatization can be prevented by decreasing the temperature to 23 °C, removing air from the derivatization reaction and adding ethanethiol.

Serum levels of protein oxidation products in patients with nickel allergy

2009 ◽  
Vol 30 (5) ◽  
pp. 552-557 ◽  
Author(s):  
Sebastiano Gangemi ◽  
Luisa Ricciardi ◽  
Paola Lucia Minciullo ◽  
Mariateresa Cristani ◽  
Salvatore Saitta ◽  
...  
Keyword(s):  
Protein Oxidation ◽  
Serum Levels ◽  
Oxidation Products ◽  
Nickel Allergy

Chemistry of the Podocarpaceae. XXXIV. Some oxidation products of (13R)-Labda-8(17),14-dien-13-ol (Manool)

1971 ◽  
Vol 24 (11) ◽  
pp. 2365 ◽  
Author(s):  
RC Cambie ◽  
KN Joblin ◽  
AF Preston
Keyword(s):  
Nucleophilic Substitution ◽  
Potassium Permanganate ◽  
Hydroxy Acid ◽  
Methyl Ketone ◽  
Major Product ◽  
Oxidation Products ◽  
Lithium Aluminium Hydride ◽  
Methyl Ketones ◽  
Sodium Dichromate ◽  
Lithium Aluminium

Some products from the oxidation of manool (3) are examined. Potassium permanganate gives, inter alia, the hitherto unreported compound (16) while sodium dichromate gives the methyl ketone (5) and, as the major product, a mixture of (Z)- and (E)-α,β-unsaturated aldehydes (21). Hypoiodite oxidation of the methyl ketone (5) gives the α-hydroxy acid (26) in addition to the expected acid (6). Products of nucleophilic substitution have also been obtained from the hypoiodite oxidation of the methyl ketones (9) and (37). Peracid oxidation of the methyl ketone (5) gives the epoxy acetate (41) which, on reduction with lithium aluminium hydride, affords the diol (7), from which the odoriferous oxide (30) can be prepared. Oxidations leading to formation of the dione (10) are investigated.

scholarly journals Labile iron pool correlates with iron content in the nucleus and the formation of oxidative DNA damage in mouse lymphoma L5178Y cell lines.

2003 ◽  
Vol 50 (1) ◽  
pp. 211-215 ◽  
Author(s):  
Marcin Kruszewski ◽  
Teresa Iwaneńko
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Cell Lines ◽  
Oxidative Dna Damage ◽  
Transition Metal Ions ◽  
Dna Lesions ◽  
Labile Iron Pool ◽  
Labile Iron ◽  
Iron Pool ◽  
Mouse Lymphoma

Labile iron pool (LIP) constitutes a crossroad of metabolic pathways of iron-containing compounds and is midway between the cellular need for iron, its uptake and storage. In this study we investigated oxidative DNA damage in relation to the labile iron pool in a pair of mouse lymphoma L5178Y (LY) sublines (LY-R and LY-S) differing in sensitivity to hydrogen peroxide. The LY-R cells, which are hydrogen peroxide-sensitive, contain 3 times more labile iron than the hydrogen peroxide-resistant LY-S cells. Using the comet assay, we compared total DNA breakage in the studied cell lines treated with hydrogen peroxide (25 microM for 30 min at 4 degrees C). More DNA damage was found in LY-R cells than in LY-S cells. We also compared the levels of DNA lesions sensitive to specific DNA repair enzymes in both cell lines treated with H(2)O(2). The levels of endonuclease III-sensitive sites and Fapy-DNA glycosylase-sensitive sites were found to be higher in LY-R cells than in LY-S cells. Our data suggest that the sensitivity of LY-R cells to H(2)O(2) is partially caused by the higher yield of oxidative DNA damage, as compared to that in LY-S cells. The critical factor appears to be the availability of transition metal ions that take part in the OH radical-generating Fenton reaction (very likely in the form of LIP).

Chemical Stability of Proteins in Foods: Oxidation and the Maillard Reaction

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Mahesha M. Poojary ◽  
Marianne N. Lund
Keyword(s):  
Maillard Reaction ◽  
Protein Oxidation ◽  
Oxidation Products ◽  
Protein Carbonyls ◽  
Annual Review ◽  
Publication Date ◽  
Food Protein ◽  
Food Proteins ◽  
Wide Range ◽  
Specific Oxidation

Protein is a major nutrient present in foods along with carbohydrates and lipids. Food proteins undergo a wide range of modifications during food production, processing, and storage. In this review, we discuss two major reactions, oxidation and the Maillard reaction, involved in chemical modifications of food proteins. Protein oxidation in foods is initiated by metal-, enzyme-, or light-induced processes. Food protein oxidation results in the loss of thiol groups and the formation of protein carbonyls and specific oxidation products of cysteine, tyrosine, tryptophan, phenylalanine, and methionine residues, such as disulfides, dityrosine, kynurenine, m-tyrosine, and methionine sulfoxide. The Maillard reaction involves the reaction of nucleophilic amino acid residues with reducing sugars, which yields numerous heterogeneous compounds such as α-dicarbonyls, furans, Strecker aldehydes, advanced glycation end-products, and melanoidins. Both protein oxidation and the Maillard reaction result in the loss of essential amino acids but may positively or negatively impact food structure and flavor. Expected final online publication date for the Annual Review of Food Science and Technology, Volume 13 is March 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Oxidative DNA Damage Defense Systems in Avoidance of Stationary-Phase Mutagenesis in Pseudomonas putida

2007 ◽  
Vol 189 (15) ◽  
pp. 5504-5514 ◽  
Author(s):  
Signe Saumaa ◽  
Andres Tover ◽  
Mariliis Tark ◽  
Radi Tegova ◽  
Maia Kivisaar
Keyword(s):  
Dna Damage ◽  
Oxidative Damage ◽  
Stationary Phase ◽  
Pseudomonas Putida ◽  
Dna Polymerase ◽  
Oxidative Dna Damage ◽  
Oxidation Products ◽  
Base Substitution ◽  
Repair Enzymes ◽  
Starvation Conditions

ABSTRACT Oxidative damage of DNA is a source of mutation in living cells. Although all organisms have evolved mechanisms of defense against oxidative damage, little is known about these mechanisms in nonenteric bacteria, including pseudomonads. Here we have studied the involvement of oxidized guanine (GO) repair enzymes and DNA-protecting enzyme Dps in the avoidance of mutations in starving Pseudomonas putida. Additionally, we examined possible connections between the oxidative damage of DNA and involvement of the error-prone DNA polymerase (Pol)V homologue RulAB in stationary-phase mutagenesis in P. putida. Our results demonstrated that the GO repair enzymes MutY, MutM, and MutT are involved in the prevention of base substitution mutations in carbon-starved P. putida. Interestingly, the antimutator effect of MutT was dependent on the growth phase of bacteria. Although the lack of MutT caused a strong mutator phenotype under carbon starvation conditions for bacteria, only a twofold increased effect on the frequency of mutations was observed for growing bacteria. This indicates that MutT has a backup system which efficiently complements the absence of this enzyme in actively growing cells. The knockout of MutM affected only the spectrum of mutations but did not change mutation frequency. Dps is known to protect DNA from oxidative damage. We found that dps-defective P. putida cells were more sensitive to sudden exposure to hydrogen peroxide than wild-type cells. At the same time, the absence of Dps did not affect the accumulation of mutations in populations of starved bacteria. Thus, it is possible that the protective role of Dps becomes essential for genome integrity only when bacteria are exposed to exogenous agents that lead to oxidative DNA damage but not under physiological conditions. Introduction of the Y family DNA polymerase PolV homologue rulAB into P. putida increased the proportion of A-to-C and A-to-G base substitutions among mutations, which occurred under starvation conditions. Since PolV is known to perform translesion synthesis past damaged bases in DNA (e.g., some oxidized forms of adenine), our results may imply that adenine oxidation products are also an important source of mutation in starving bacteria.

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