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Kritsky, M. S.; Телегина, Т. А.; Lyudnikova, T. A.; Umrikhina, A. V.; Zemskova, Yu. L.

doi:10.1023/a:1012344210189

Cited by 5 publications

(4 citation statements)

References 2 publications

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“…The cation radical was also relatively stable and had a very slow rate of dismutation , or reaction with O 2 . ,, These cation radicals were considered to be protonated at N5, which was suggested to decrease the reactivity of the H 4 B •+ species. In some cases UV or EPR spectra of neutral, cationic, and anionic biopterin radicals were also reported. How the structure of the resulting radical differs from the parent structure is unknown.…”

Section: Pterin Radical Generated From Chemical Reactionsmentioning

confidence: 99%

Tetrahydrobiopterin Radical Enzymology

2003

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Section: Pterin Radical Generated From Chemical Reactionsmentioning

confidence: 99%

Tetrahydrobiopterin Radical Enzymology

2003

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“…Secondly, independently of these observations, a study of the basic photophysical and photochemical properties of biological pterins was started. It was found that (1) pterin molecules are active in electron transfer processes, including the oxidation of high-potential donors, which occurs with the participation of free radical forms [ 12 , 13 ]; and (2) the properties of excited pterin triplets were characterized and it was shown that pterin molecules are photogenerators of singlet oxygen with a quantum yield of up to 47% [ 14 ]. In subsequent works, the mechanisms of a number of photoinduced redox reactions involving excited pterins have been revealed [ 15 , 16 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

“…It has now become clear that the list of pterins involved in photoreception is not limited to MTHF, but also includes unconjugated pterins: cyanopterin [ 21 ] and 5,6,7,8-tetrahydrobiopterin (H 4 Bip) [ 22 ]. In studies of pterin photonics, the interest has been directed to reduced molecules [ 12 , 13 , 23 , 24 , 25 , 26 ] since reduced pterins predominantly function in the cell as cofactors of enzymatic reactions.…”

Section: Introductionmentioning

confidence: 99%

Insights into Molecular Structure of Pterins Suitable for Biomedical Applications

Buglak

Kapitonova

Vechtomova

et al. 2022

IJMS

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Pterins are an inseparable part of living organisms. Pterins participate in metabolic reactions mostly as tetrahydropterins. Dihydropterins are usually intermediates of these reactions, whereas oxidized pterins can be biomarkers of diseases. In this review, we analyze the available data on the quantum chemistry of unconjugated pterins as well as their photonics. This gives a comprehensive overview about the electronic structure of pterins and offers some benefits for biomedicine applications: (1) one can affect the enzymatic reactions of aromatic amino acid hydroxylases, NO synthases, and alkylglycerol monooxygenase through UV irradiation of H4pterins since UV provokes electron donor reactions of H4pterins; (2) the emission properties of H2pterins and oxidized pterins can be used in fluorescence diagnostics; (3) two-photon absorption (TPA) should be used in such pterin-related infrared therapy because single-photon absorption in the UV range is inefficient and scatters in vivo; (4) one can affect pathogen organisms through TPA excitation of H4pterin cofactors, such as the molybdenum cofactor, leading to its detachment from proteins and subsequent oxidation; (5) metal nanostructures can be used for the UV-vis, fluorescence, and Raman spectroscopy detection of pterin biomarkers. Therefore, we investigated both the biochemistry and physical chemistry of pterins and suggested some potential prospects for pterin-related biomedicine.

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“…It has been shown that the excited heterocycle enters photochemical reactions and that this is accompanied by a change of reduction degree. In the presence of electron donors, pterins (e.g., 6,7-dimethylpterin) undergo one-and two-electron photoreduction [4,5]. Photochemical activity can be also the result of formation of singlet oxygen by some pterins [6][7][8].…”

mentioning

confidence: 99%

Resistance of 5,10-methenyltetrahydrofolate to ultraviolet radiation

Телегина

Lyudnikova

Zemskova

et al. 2005

Appl Biochem Microbiol

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Aeration of aqueous solutions of 5,10-methenyltetrahydrofolic acid (MTHF) during exposure to ultraviolet irradiation ( λ = 300-390 nm, 240 W/m 2 , 30 min) slowed down photolysis in comparison with deaerated solutions. The rate of photolysis in the presence of oxygen depended on the ionic strength of the buffer composition. MTHF degradation did not exceed 6% of the starting amount of MTHF. Photolysis of MTHF included opening of the imidazoline ring, dehydrogenation of the tetrahydropterin heterocycle, and elimination of the p -aminobenzoylglutamate moiety. 6,7-Dimethyltetrahydropterin was used as a model compound to show that protonation of the reduced pterin heterocycle increased its resistance to oxidation, and UV irradiation did not accelerate this process. The stabilizing effect of protonation of the pterin portion and the presence of the positively charged imidazoline moiety are assumed to hamper MTHF oxidation and photolysis. It is assumed that these factors favored the choice of MTHF molecules as photosensors in radiation-sensitive proteins in the course of evolution.

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Untitled

Cited by 5 publications

References 2 publications

Tetrahydrobiopterin Radical Enzymology

Tetrahydrobiopterin Radical Enzymology

Insights into Molecular Structure of Pterins Suitable for Biomedical Applications

Resistance of 5,10-methenyltetrahydrofolate to ultraviolet radiation

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