5-S-Cysteinyldopa, a diffusible product of melanocyte activity, is an efficient inhibitor of hydroxylation/oxidation reactions induced by the Fenton system

Napolitano, Alessandra; Memoli, Sofia; Nappi, Anthony J.; d’Ischia, Marco; Prota, Giuseppe

doi:10.1016/0304-4165(96)00047-5

Cited by 34 publications

(30 citation statements)

References 22 publications

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“…That lipid peroxidation was not increased may be due to ROS scavenging by antioxidant enzymes and/or suppression of ROS generation by cysteinyldopa and quinoprotein formation through the binding of dopaquinone and dopaminequinone with cysteine. 10,30,31) Another research group hypothesized that l-DOPA inhibited growth of soybean may be by activation of a phenylalanine ammonia-lyase (PAL) and phenylpropanoid pathway thus accumulating phenolic compounds-including lignin-and increasing peroxidase activity.…”

Section: Discussionmentioning

confidence: 99%

Bioactive l-DOPA induced quinoprotein formation to inhibit root growth of cucumber seedlings

2013

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l-DOPA (l-3,4-dihydroxyphenylalanine) is a bioactive secondary metabolite which inhibits growth of many weed species. However, its mode of action is not well elucidated in plants. The present studies were conducted to evaluate the effect of l-DOPA on root growth of cucumber (Cucumis sativus L.) and the possible involvement of quinoproteins (quinone-incorporated proteins) in phytotoxicity of l-DOPA. The results revealed that l-DOPA significantly inhibited root growth, induced cell death, increased polyphenol oxidase (PPO) activity, reduced free cysteine content, and enhanced quinoprotein formation in cucumber roots. The decrease in free cysteine content and increase in PPO activity suggested that quinones covalently bind with cysteine to form quinoproteins. The quinoproteins may be involved in phytotoxic action of l-DOPA in cucumber roots.

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Section: Discussionmentioning

confidence: 99%

Bioactive l-DOPA induced quinoprotein formation to inhibit root growth of cucumber seedlings

2013

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“…This was the case for 5SCD and structurally related model compounds (44). The strong ability of 5SCD to complex iron ions accounts for its inhibitory action on the Fenton type decomposition of hydrogen peroxide to hydroxyl radicals (45). On oxidation, the 5SCD iron‐chelate gives rise to benzothiazole species (46), whereas zinc complexation results in a noticeable stabilization of pheomelanogenic intermediates at the benzothiazine stage favoring the formation of the 3‐carboxy‐1,4‐benzothiazine and on further oxidation of 2,2′‐bibenzothiazine dimers (14,15,47).…”

Section: Discussionmentioning

confidence: 99%

Zinc‐induced Structural Effects Enhance Oxygen Consumption and Superoxide Generation in Synthetic Pheomelanins on UVA/Visible Light Irradiation^†

Panzella

Szewczyk

d’Ischia

et al. 2010

Photochem & Photobiology

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The abnormal susceptibility of red-haired individuals to UV-induced inflammation and skin cancers is commonly attributed to the marked photoreactivity of pheomelanin pigments, which would be responsible for the sustained generation of reactive oxygen species in the skin following sun exposure. The structural factors determining pheomelanin photolability remain mostly unknown. Here, we describe the effects of zinc ions, typically found at high levels in red hair, in enhancing both oxygen consumption and superoxide production in model pheomelanin pigments following irradiation with UVA and visible light. Electron paramagnetic resonance (EPR) oximetry and EPR-spin trapping experiments with synthetic pheomelanins, prepared by oxidation of dopa and cysteine or isomeric cysteinyldopas under different conditions, indicate a higher photoreactivity of the pigments prepared in the presence of zinc ions compared with those obtained in the absence of the metal. Quantitative analysis of thiazole-containing structural markers of the synthetic pheomelanins provides evidence that the effect of zinc ions is due to modification of the formation pathway and structural features of the pigments. Overall, these results point to a hitherto unrecognized critical role of zinc ions in pheomelanogenesis, which may affect the intrinsic photoreactivity of the pigment.

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“…Finally, a role for both free and protein‐DOPA in cellular antioxidant defenses was suggested (Nelson et al., 2010), and inhibition of lipoxygenase‐mediated arachidonic acid oxygenation by DHI and to lesser degree by DHICA was demonstrated (Napolitano et al., 1993). Also, diffusible melanin‐related metabolites are potent inhibitors of lipid peroxidation (Memoli et al., 1997), and 5‐S‐cysteinyldopa inhibits hydroxylation/oxidation reactions induced by the Fenton system (Napolitano et al., 1996). The potential cycling from the indole to the quinone form of L‐DOPA and its derivatives may have direct effects on deactivation of reactive oxygen/nitrogen species or oxidation of intracellular proteins and lipids, most probably in a concentration‐dependent manner (Tsang and Chung, 2009).…”

Section: Mechanism Of Action For L‐tyrosine and L‐dopamentioning

confidence: 99%

L‐tyrosine and L‐dihydroxyphenylalanine as hormone‐like regulators of melanocyte functions

Slominski

Żmijewski

Pawelek

2011

Pigment Cell Melanoma Res

375

336

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Summary Evidence reveals that L-tyrosine and L-DOPA, besides serving as substrates and intermediates of melanogenesis, are also bioregulatory agents acting not only as inducers and positive regulators of melanogenesis but also as regulators of other cellular functions. These can be mediated through action on specific receptors or through non-receptor mediated mechanisms. The substrate induced (L-tyrosine and/or L-DOPA) melanogenic pathway would autoregulate itself as well as it would regulate the melanocyte functions through activity of its structural or regulatory proteins and through intermediates of melanogenesis and melanin itself. Dissection of regulatory and autoregulatory elements of this process may elucidate how substrate induced autoregulatory pathways have evolved from prokaryotic or simple eukaryotic organisms to complex systems in vertebrates. This could substantiate older theory proposing that receptors for amino-acid derived hormones arose from the receptors for those amino acids, and that nuclear receptors evolved from primitive intracellular receptors binding nutritional factors or metabolic intermediates.

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5-S-Cysteinyldopa, a diffusible product of melanocyte activity, is an efficient inhibitor of hydroxylation/oxidation reactions induced by the Fenton system

Cited by 34 publications

References 22 publications

Bioactive l-DOPA induced quinoprotein formation to inhibit root growth of cucumber seedlings

Bioactive l-DOPA induced quinoprotein formation to inhibit root growth of cucumber seedlings

Zinc‐induced Structural Effects Enhance Oxygen Consumption and Superoxide Generation in Synthetic Pheomelanins on UVA/Visible Light Irradiation^†

L‐tyrosine and L‐dihydroxyphenylalanine as hormone‐like regulators of melanocyte functions

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5-S-Cysteinyldopa, a diffusible product of melanocyte activity, is an efficient inhibitor of hydroxylation/oxidation reactions induced by the Fenton system

Cited by 34 publications

References 22 publications

Bioactive l-DOPA induced quinoprotein formation to inhibit root growth of cucumber seedlings

Bioactive l-DOPA induced quinoprotein formation to inhibit root growth of cucumber seedlings

Zinc‐induced Structural Effects Enhance Oxygen Consumption and Superoxide Generation in Synthetic Pheomelanins on UVA/Visible Light Irradiation†

L‐tyrosine and L‐dihydroxyphenylalanine as hormone‐like regulators of melanocyte functions

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Zinc‐induced Structural Effects Enhance Oxygen Consumption and Superoxide Generation in Synthetic Pheomelanins on UVA/Visible Light Irradiation^†