Soybean phosphatidylcholine liposomes as model membranes to study lipid peroxidation photoinduced by pterin

Thomas, Andrés H.; Catalá, Ángel; Vignoni, Mariana

doi:10.1016/j.bbamem.2015.11.002

Cited by 45 publications

(42 citation statements)

References 36 publications

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“…Dihydro and oxidized pterin derivatives accumulate in the affected tissues at concentrations that are significantly higher than those reported for healthy cells [20,21]. Although intracellular concentrations were not determined, it can be assumed that pterins can reach any cellular compartment since these compounds can freely cross phospholipid membranes [22].…”

Section: Introductionmentioning

confidence: 95%

Photosensitization of peptides and proteins by pterin derivatives

et al. 2017

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Proteins are one of the preferential targets of the photosensitized damaging effects of ultraviolet (UV) radiation on biological system. Pterins belong to a family of heterocyclic compounds, which are widespread in living systems and participate in relevant biological functions. In pathological conditions, such as vitiligo, oxidized pterins accumulate in the white skin patches of patients suffering this depigmentation disorder. It is known that pterins are able to photosensitize damage in nucleotides and DNA by type I (electron transfer) and type II (singlet oxygen) mechanisms. Recently, it has been demonstrated that proteins and its components may also be damaged when solutions containing both proteins and pterin are exposed to UV-A radiation. Therefore, given the biological and medical relevance of the photosensitizing properties of these molecules, we present in this article an overview of the capability of different pterin derivatives to photoinduce damage in proteins present in the skin, focusing our attention on the chemical modifications of tyrosine and tryptophan residues.

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Section: Introductionmentioning

confidence: 95%

Photosensitization of peptides and proteins by pterin derivatives

et al. 2017

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“…Relative enthalpies in kcal mol À1 of the pterin isomers and transition states are shown. The [1,3]-and [1,4]-methyl shifts require very high activation energies. Thus, it is logical to conclude that the O-and N-alkyl pterins, for example, 3 and 4, are non-interconverting species, unlike walk processes observed for molecular rearrangements (33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43), such as the walk rearrangement of bicyclo[2.1.0]pent-2ene (44).…”

Section: Dft Computed Stabilities Of Alkyl Pterin Regioisomersmentioning

confidence: 99%

“…Despite their low solubility in every solvent, a number of studies have been performed on the photochemistry of pterin sensitizers (1)(2)(3)(4)(5). A N-methyl pterin 2 (6) as well as other pterin derivatives (7) have been previously reported.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Control in the Regioselective Alkylation of Pterin Sensitizers: A Synthetic, Photochemical, and Theoretical Study

Walalawela

Vignoni

Urrutia

et al. 2018

Photochem & Photobiology

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Alkylation patterns and excited-state properties of pterins were examined both experimentally and theoretically. 2D NMR spectroscopy was used to characterize the pterin derivatives, revealing undoubtedly that the decyl chains were coupled to either the O4 or N3 sites on the pterin. At a temperature of 70°C, the pterin alkylation regioselectively favored the O4 over the N3. The O4 was also favored when using solvents, in which the reactants had increased solubility, namely N,N-dimethylformamide and N,N-dimethylacetamide, rather than solvents in which the reactants had very low solubility (tetrahydrofuran and dichloromethane). Density functional theory (DFT) computed enthalpies correlate to regioselectivity being kinetically driven because the less stable O-isomer forms in higher yield than the more stable N-isomer. Once formed these compounds did not interconvert thermally or undergo a unimolecular "walk" rearrangement. Mechanistic rationale for the factors underlying the regioselective alkylation of pterins is suggested, where kinetic rather than thermodynamic factors are key in the higher yield of the O-isomer. Computations also predicted greater solubility and reduced triplet state energetics thereby improving the properties of the alkylated pterins as O sensitizers. Insight on thermal and photostability of the alkylated pterins is also provided.

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“…However, they are also present in different biological systems and play various roles. Nowadays, it is known that besides acting as pigments (2), pterins participate in other relevant biological functions; this includes being the lightharvesting antenna of DNA photolyases, enzymes involved in DNA repair processes after UV irradiation (3)(4)(5), as well as behaving as coenzymes (6,7), enzymes inhibitors (8) and sensitizers of different biological targets (9)(10)(11)(12)(13)(14).…”

Section: Introductionmentioning

confidence: 99%

Photophysical and Photochemical Properties of 3‐methylpterin as a New and More Stable Pterin‐type Photosensitizer

Estébanez

Lorente

Kaufman

et al. 2018

Photochem & Photobiology

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Pterin derivatives are heterocyclic compounds which are present in different biological systems. Neutral aqueous solutions of pterins present acid-base and keto-enol equilibria. These compounds, under UV-A radiation fluoresce, undergo photooxidation, generate reactive oxygen species and photoinduce the oxidation of biological substrates. As photosensitizers, they may act through different mechanisms, mainly through an electron transfer-initiated process (type-I mechanism), but they also produce singlet molecular oxygen ( O ) upon irradiation (type-II mechanism). In general, upon UV-A excitation two triplet states, corresponding to the lactim and lactam tautomers, are formed, but only the last one is the responsible for the photosensitized reactions of biomolecules. We present a study of the photochemical properties of 3-methylpterin (3-Mep) which, in contrast to most pterin derivatives, exists only in the lactam form. Also an improvement in the synthesis of 3-Mep is reported. The spectroscopic properties 3-Mep in aqueous solution were similar to those of the unsubstituted pterin derivative (Ptr) in its acid form, such as absorption, fluorescent and phosphorescent emission spectra. Experiments using 2'-deoxyguanosine 5'-monophosphate (dGMP) as oxidizable target demonstrated that methylation at C-3 position of the pterin moiety does not affect significantly the efficiency of photosensitization, but results in a more photostable sensitizer.

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Soybean phosphatidylcholine liposomes as model membranes to study lipid peroxidation photoinduced by pterin

Cited by 45 publications

References 36 publications

Photosensitization of peptides and proteins by pterin derivatives

Photosensitization of peptides and proteins by pterin derivatives

Kinetic Control in the Regioselective Alkylation of Pterin Sensitizers: A Synthetic, Photochemical, and Theoretical Study

Photophysical and Photochemical Properties of 3‐methylpterin as a New and More Stable Pterin‐type Photosensitizer

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