Photooxidation of Tetrahydrobiopterin under UV Irradiation: Possible Pathways and Mechanisms

Buglak, Andrey A.; Телегина, Т. А.; Lyudnikova, T. A.; Vechtomova, Yulia L.; Kritsky, M. S.

doi:10.1111/php.12285

Cited by 22 publications

(20 citation statements)

References 30 publications

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“…The fluorescence quantum yields (Φ F ) were determined from the corrected fluorescence spectra using eq : where I is the integrated intensity, A is the absorbance at the excitation wavelength (λ exc ), and the superscript R refers to the reference fluorophore. In our experiments Ptr in alkaline media (Φ F = 0.27) and quinine bisulfate (Riedel-de Haën, Seelze, Germany) in 0.5 M H 2 SO 4 (Φ F = 0.546) were used as reference. To avoid inner filter effects, the absorbance of the solutions, at the excitation wavelength, was kept below 0.10.…”

Section: Methodsmentioning

confidence: 99%

Lipophilic Decyl Chain–Pterin Conjugates with Sensitizer Properties

et al. 2017

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A new series of decyl chain [-(CH)CH] pterin conjugates have been investigated by photochemical and photophysical methods, and with theoretical solubility calculations. To synthesize the pterins, a nucleophilic substitution (S2) reaction was used for the regioselective coupling of the alkyl chain to the O site over the N site. However, the O-alkylated pterin converts to N-alkylated pterin under basic conditions, pointing to a kinetic product in the former and a thermodynamic product in the latter. Two additional adducts were also obtained from an N-amine condensation of DMF solvent molecule as byproducts. In comparison to the natural product pterin, the alkyl chain pterins possess reduced fluorescence quantum yields (Φ) and increased singlet oxygen quantum yields (Φ). It is shown that the DMF-condensed pterins were more photostable compared to the N- and O-alkylated pterins bearing a free amine group. The alkyl chain pterins efficiently intercalate in large unilamellar vesicles, which is a good indicator of their potential use as photosensitizers in biomembranes. Our study serves as a starting point where the synthesis can be expanded to produce a wider series of lipophilic, photooxidatively active pterins.

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Section: Methodsmentioning

confidence: 99%

Lipophilic Decyl Chain–Pterin Conjugates with Sensitizer Properties

et al. 2017

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“…The etiology of vitiligo is still unknown, but its relationship with the metabolism of aromatic amino acids (Phe, Tyr, DOPA, Trp) is known for certain [ 16 ]. Redox reactions of Tyr and DOPA [ 17 , 18 ], as well as their interplay with pterin photoreactions [ 19 , 20 , 21 , 22 , 23 ] are of great importance for melanogenesis and vitiligo etiology/treatment [ 24 , 25 , 26 , 27 , 28 ]. In this regard, biosensors based on metal NCs can be used for cost-effective diagnostics of vitiligo and other Tyr metabolism-related diseases.…”

Section: Introductionmentioning

confidence: 99%

Silver Cluster Interactions with Tyrosine: Towards Amino Acid Detection

Buglak

Kononov

2022

IJMS

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Tyrosine (Tyr) is involved in the synthesis of neurotransmitters, catecholamines, thyroid hormones, etc. Multiple pathologies are associated with impaired Tyr metabolism. Silver nanoclusters (Ag NCs) can be applied for colorimetric, fluorescent, and surface-enhanced Raman spectroscopy (SERS) detection of Tyr. However, one should understand the theoretical basics of interactions between Tyr and Ag NCs. Thereby, we calculated the binding energy (Eb) between Tyr and Agnq (n = 1–8; q = 0–2) NCs using the density functional theory (DFT) to find the most stable complexes. Since Ag NCs are synthesized on Tyr in an aqueous solution at pH 12.5, we studied Tyr−1, semiquinone (SemiQ−1), and Tyr−2. Ag32+ and Ag5+ had the highest Eb. The absorption spectrum of Tyr−2 significantly red-shifts with the attachment of Ag32+, which is prospective for colorimetric Tyr detection. Ag32+ interacts with all functional groups of SemiQ−1 (phenolate, amino group, and carboxylate), which makes detection of Tyr possible due to band emergence at 1324 cm−1 in the vibrational spectrum. The ground state charge transfer between Ag and carboxylate determines the band emergence at 1661 cm−1 in the Raman spectrum of the SemiQ−1–Ag32+ complex. Thus, the prospects of Tyr detection using silver nanoclusters were demonstrated.

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“…Therefore, under irradiation of skin affected by vitiligo, Fop and Cap are formed, very likely, due to the photolysis of both PteGlu and H 4 Bip [57][58][59]. In fact, Cap has been isolated from the skin of patients suffering from vitiligo [21].…”

Section: Photoinactivation Of Tyrosinasementioning

confidence: 99%

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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Photooxidation of Tetrahydrobiopterin under UV Irradiation: Possible Pathways and Mechanisms

Cited by 22 publications

References 30 publications

Lipophilic Decyl Chain–Pterin Conjugates with Sensitizer Properties

Lipophilic Decyl Chain–Pterin Conjugates with Sensitizer Properties

Silver Cluster Interactions with Tyrosine: Towards Amino Acid Detection

Photosensitization of peptides and proteins by pterin derivatives

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