کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10739121 | 1046862 | 2005 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Intra- and intermolecular oxidation of oxymyoglobin and oxyhemoglobin induced by hydroxyl and carbonate radicals
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کلمات کلیدی
TrpOxyhemoglobinPHECysBSA - BSAOH radical - OH رادیکالbovine serum albumin - آلبومین سرم گاوOxymyoglobin - اکسیمیوگلوبینphosphate buffer - بافر فسفاتTryptophan - تریپتوفانTyr - تیرTyrosine - تیروزینHIS - خودCarbonate radical - رادیکال کربناتCysteine - سیستئینKinetics - سینتیک (جنبش شناسی) Phenylalanine - فنیلآلانینMetmyoglobin - متمیوگلوبینmethemoglobin - متهموگلوبینMethionine - متیونینMET - ملاقات کردhistidine - هیستیدینRadiolysis - پرتوکافت، رادیولیزHeme protein - پروتئین هام
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
سالمندی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The mechanism of the reactions of myoglobin and hemoglobin with OH and CO3â in the presence of oxygen was studied using pulse and γ-radiolysis. Unlike NO2, which adds to the porphyrin iron, OH and CO3â form globin radicals. These secondary radicals oxidize the FeII center through both intra- and intermolecular processes. The intermolecular pathway was further demonstrated when BSA radicals derived from OH or CO3â oxidized oxyhemoglobin and oxymyoglobin to their respective ferric states. The oxidation yields obtained by pulse radiolysis were lower compared to γ-radiolysis, where the contribution of radical-radical reactions is negligible. Full oxidation yields by OH-derived globin radicals could be achieved only at relatively high concentrations of the heme protein mainly via an intermolecular pathway. It is suggested that CO3â reaction with the protein yields Tyr and/or Trp-derived phenoxyl radicals, which solely oxidize the porphyrin iron under γ-radiolysis conditions. The OH particularly adds to aromatic residues, which can undergo elimination of H2O forming the phenoxyl radical, and/or react rapidly with O2 yielding peroxyl radicals. The peroxyl radical can oxidize a neighboring porphyrin iron and/or give rise to superoxide, which neither oxidize nor reduce the porphyrin iron. The potential physiological implications of this chemistry are that hemoglobin and myoglobin, being present at relatively high concentrations, can detoxify highly oxidizing radicals yielding the respective ferric states, which are not toxic.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Free Radical Biology and Medicine - Volume 39, Issue 4, 15 August 2005, Pages 511-519
Journal: Free Radical Biology and Medicine - Volume 39, Issue 4, 15 August 2005, Pages 511-519
نویسندگان
Sara Goldstein, Amram Samuni,