Transformation of 6-tetrahydrobiopterin in aqueous solutions under UV-irradiation

Телегина, Т. А.; Lyudnikova, T. A.; Buglak, Andrey A.; Vechtomova, Yulia L.; Biryukov, Mikhail V.; Демин, В. В.; Kritsky, M. S.

doi:10.1016/j.jphotochem.2017.07.029

Cited by 14 publications

(18 citation statements)

References 25 publications

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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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Section: Introductionmentioning

confidence: 99%

Silver Cluster Interactions with Tyrosine: Towards Amino Acid Detection

Buglak

Kononov

2022

IJMS

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“…The pathophysiology of H4Bip remains an open field of investigation as evidenced by the recent disclosure of a genetic disorder of neurotransmitter translocation into synaptic vesicles or by the renewed interest in its pathophysiological role in vitiligo. , More recently, H4Bip was also found to be involved in autoimmunity and cancer . It was also suggested that this molecule could be a biomarker for kidney injury in diabetes …”

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confidence: 99%

“…These values were determined at different pH values and using different buffer types which are known to strongly affect oxidation pathways . In this respect, it has been reported that H4Bip is resistant to oxidation by oxygen at acidic pH, which is particularly unexpected. Finally, in biological samples, H4Bip may oxidize within minutes, without a molar relationship between the loss of H4Bip and increase of H2Bip and Bip in terms of the concentration …”

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confidence: 99%

Multianalytical Approach for Deciphering the Specific MS/MS Transition and Overcoming the Challenge of the Separation of a Transient Intermediate, Quinonoid Dihydrobiopterin

et al. 2022

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Despite recent technological developments in analytical chemistry, separation and direct characterization of transient intermediates remain an analytical challenge. Among these, separation and direct characterization of quinonoid dihydrobiopterin (qH2Bip), a transient intermediate of tetrahydrobiopterin (H4Bip)-dependent hydroxylation reactions, essential in living organisms, with important and varied human pathophysiological impacts, are a clear illustration. H4Bip regeneration may be impaired by competitive nonenzymatic autoxidation reactions, such as isomerization of qH2Bip into a more stable 7,8-H2Bip (H2Bip) isomer, and subsequent nonenzymatic oxidation reactions. The quinonoid qH2Bip intermediate thus plays a key role in H4Bip-dependent hydroxylation reactions. However, only a few experimental results have indirectly confirmed this finding while revealing the difficulty of isolating qH2Bip from H4Bip-containing solutions. As a result, no current H4Bip assay method allows this isomer to be quantified even by liquid chromatography–tandem mass spectrometry (MS/MS). Here, we report isolation, structural characterization, and abundance of qH2Bip formed upon H4Bip autoxidation using three methods integrated into MS/MS. First, we characterized the structure of the two observed H2B isomers using IR photodissociation spectroscopy in conjunction with quantum chemical calculations. Then, we used differential ion mobility spectrometry to fully separate all oxidized forms of H4Bip including qH2Bip. These data are consistent and show that qH2Bip can also be unambiguously identified thanks to its specific MS/MS transition. This finding paves the way for the quantification of qH2Bip with MS/MS methods. Most importantly, the half-life value of this intermediate is nearly equivalent to that of H4Bip (tens of minutes), suggesting that an accurate method of H4Bip analysis should include the quantification of qH2Bip.

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“…In turn, the process of melanogenesis can be disrupted when exposed to various exogenous etiological environmental factors, including UV [ 30 ]. Disruption of melanogenesis occurs in a number of dermatological diseases, including vitiligo [ 31 , 32 , 33 ]. The study of melanogenesis and the ways of its regulation are important for the development of new photoprotective strategies for the prevention of skin cancer.…”

Section: Possible Mechanisms Of Dna Damage By Uv Radiationmentioning

confidence: 99%

UV Radiation in DNA Damage and Repair Involving DNA-Photolyases and Cryptochromes

et al. 2021

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Prolonged exposure to ultraviolet radiation on human skin can lead to mutations in DNA, photoaging, suppression of the immune system, and other damage up to skin cancer (melanoma, basal cell, and squamous cell carcinoma). We reviewed the state of knowledge of the damaging action of UVB and UVA on DNA, and also the mechanisms of DNA repair with the participation of the DNA-photolyase enzyme or of the nucleotide excision repair (NER) system. In the course of evolution, most mammals lost the possibility of DNA photoreparation due to the disappearance of DNA photolyase genes, but they retained closely related cryptochromes that regulate the transcription of the NER system enzymes. We analyze the published relationships between DNA photolyases/cryptochromes and carcinogenesis, as well as their possible role in the prevention and treatment of diseases caused by UV radiation.

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Transformation of 6-tetrahydrobiopterin in aqueous solutions under UV-irradiation

Cited by 14 publications

References 25 publications

Silver Cluster Interactions with Tyrosine: Towards Amino Acid Detection

Silver Cluster Interactions with Tyrosine: Towards Amino Acid Detection

Multianalytical Approach for Deciphering the Specific MS/MS Transition and Overcoming the Challenge of the Separation of a Transient Intermediate, Quinonoid Dihydrobiopterin

UV Radiation in DNA Damage and Repair Involving DNA-Photolyases and Cryptochromes

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