Formation of formylkynurenine by the action of X-rays on tryptophan in aqueous solution

Jayson, G. G.; Scholes, G.; Weiß, Joseph

doi:10.1042/bj0570386

Cited by 59 publications

(20 citation statements)

References 8 publications

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“…This absence of specificity is probably due to the presence of a tryptophan residue, because such residues are particularly sensitive to oxidation under various conditions (40). The reactive species OH ⅐ and H 2 O 2 react with tryptophan residues to form various oxidation products (41)(42)(43)(44). These reactive species can be formed during the P450 catalytic cycle when O 2 reduction is not coupled to substrate oxidation (45).…”

Section: Discussionmentioning

confidence: 99%

Substrate and Reaction Specificity of Mycobacterium tuberculosis Cytochrome P450 CYP121

Fonvielle

Lequin

et al. 2013

Journal of Biological Chemistry

107

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Background:Little is known about the substrate specificity of the essential P450 CYP121 from Mycobacterium tuberculosis. Results: CYP121 substrate analogues either display impaired binding to CYP121 or are poorly transformed by CYP121. Conclusion: CYP121 is a highly specific P450. Significance: This work contributes to the understanding of the function and the catalytic mechanism of CYP121 and provides novel data for the design of inhibitors.

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Section: Discussionmentioning

confidence: 99%

Substrate and Reaction Specificity of Mycobacterium tuberculosis Cytochrome P450 CYP121

Fonvielle

Lequin

et al. 2013

Journal of Biological Chemistry

107

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“…thiols, vitamin E) and if there are vicinal tyrosyl radicals [15,16]. Hydroxylation of phenylalanine, tyrosine and tryptophan is also a characteristic reaction of hydroxyl radicals [17,18], and similar reactions of histidine (giving 2-oxohistidine) are important [19]. Fenton chemistry can generate both the aliphatic and aromatic [20] products.…”

Section: Table 1 New Moieties Generated By Biological Protein Oxidatimentioning

confidence: 99%

Biochemistry and pathology of radical-mediated protein oxidation

Dean

Stocker

et al. 1997

Biochemical Journal

1,545

982

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Radical-mediated damage to proteins may be initiated by electron leakage, metal-ion-dependent reactions and autoxidation of lipids and sugars. The consequent protein oxidation is O2-dependent, and involves several propagating radicals, notably alkoxyl radicals. Its products include several categories of reactive species, and a range of stable products whose chemistry is currently being elucidated. Among the reactive products, protein hydroperoxides can generate further radical fluxes on reaction with transition-metal ions; protein-bound reductants (notably dopa) can reduce transition-metal ions and thereby facilitate their reaction with hydroperoxides; and aldehydes may participate in Schiff-base formation and other reactions. Cells can detoxify some of the reactive species, e.g. by reducing protein hydroperoxides to unreactive hydroxides. Oxidized proteins are often functionally inactive and their unfolding is associated with enhanced susceptibility to proteinases. Thus cells can generally remove oxidized proteins by proteolysis. However, certain oxidized proteins are poorly handled by cells, and together with possible alterations in the rate of production of oxidized proteins, this may contribute to the observed accumulation and damaging actions of oxidized proteins during aging and in pathologies such as diabetes, atherosclerosis and neurodegenerative diseases. Protein oxidation may also sometimes play controlling roles in cellular remodelling and cell growth. Proteins are also key targets in defensive cytolysis and in inflammatory self-damage. The possibility of selective protection against protein oxidation (antioxidation) is raised.

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“…Oxindolylalanine does not seem to be an intermediate in the reaction. Suggested mechanisms (206,300) propose 2-hydroxy-3-hydroperoxyindoline (86) as an intermediate. However, in the light of recent theories on tryptophan oxidation, which were discussed in other sections a modification of the above discussed mechanism can be also proposed which involves hydroperoxyindolenine as an intermediate.…”

Section: 3/onizing Radiationmentioning

confidence: 99%

“…The effect of ionizing radiation (x or y rays) on tryptophan or on tryptophan-containing proteins in aerated aqueous solution is seemingly to bring about partial conversion of tryptophan to formylkynurenine (5,206,300). The oxidizing species are presumed to be hydroxy and hydroperoxy radicals.…”

Section: 3/onizing Radiationmentioning

confidence: 99%