کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6493795 | 44426 | 2015 | 5 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Photoinactivation of tyrosinase sensitized by folic acid photoproducts
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کلمات کلیدی
5-MethyltetrahydrofolatePteGluBiopterinFOPTrp1O2MEPDOPAtetrahydrobiopterin3,4-dihydroxy-l-phenylalanine - 3،4-دی هیدروکسیل-فنیل آلانین6-Formylpterin - 6-فرمول پترینBiP - BIPl-Tyrosine - L-TyrosineO2− - O2-P-aminobenzoic acid - P-آمینو بنزوئیک اسیدPTr - PTRHydrogen peroxide - آب اکسیژنهsuperoxide anion - آنیون سوپر اکسیدFolic acid - اسید فولیکglutamic acid - اسید گلوتامیکUV-A radiation - اشعه ماوراء بنفش ASinglet oxygen - اکسیژن مجزاTryptophan - تریپتوفانTyr - تیرTyrosinase - تیروزیناز Volume - جلدH2O2 - هیدروژن پراکسیدPABA - پاباPterin - پترینvitiligo - پیسی، برص، لک و پیس، ویتیلیگوHPLC - کروماتوگرافی مایعی کاراhigh-performance liquid chromatography - کروماتوگرافی مایعی کاراCaP - کلاه لبه دارGlu - گلوReactive oxygen species - گونههای فعال اکسیژن
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
بیو مهندسی (مهندسی زیستی)
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Tyrosinase catalyzes in mammals the first and rate-limiting step in the biosynthesis of the melanin, the main pigment of the skin. Pterins, heterocyclic compounds able to photoinduce oxidation of biomolecules, accumulate in the skin of patients suffering from vitiligo, where there is a lack of melanin. Folic acid (PteGlu) is a conjugated pterin widespread in biological systems. Aqueous solutions of tyrosinase were exposed to UV-A irradiation (350Â nm) in the presence of PteGlu and its photoproducts (6-formylpterin and 6-carboxypterin). The reactions were followed by UV-Vis spectrophotometry, enzyme activity measurement, fluorescence spectroscopy and HPLC. In this work, we present data that demonstrate unequivocally that solutions of tyrosinase exposed to UV-A irradiation in the presence of PteGlu, undergo enzyme inactivation. However, PteGlu itself causes a negligible effect on the activity of the enzyme. In contrast, PteGlu photoproducts are efficient photosensitizers. The tyrosinase inactivation involves two different pathways: (i) a photosensitization process and (ii) the oxidation of the enzyme by the hydrogen peroxide produced during the photooxidation of PteGlu and its photoproduct. The former pathway affects both the active site and the tryptophan residues, whereas the latter affects only the active site. The biological implications of the results are discussed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 149, August 2015, Pages 172-179
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 149, August 2015, Pages 172-179
نویسندگان
M. Laura Dántola, Beatriz N. Zurbano, Andrés H. Thomas,