物理化学学报 >> 2016, Vol. 32 >> Issue (4): 872-878.doi: 10.3866/PKU.WHXB201601046

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紫外光诱导氧合型肌红蛋白氧化反应及机理

曹洪玉1,3,高凌星2,唐乾1,3,苏晋红2,郑学仿1,2,3,*()   

  1. 1 大连大学生命科学与技术学院, 辽宁大连 116622
    2 大连大学环境与化学工程学院, 辽宁大连 116622
    3 大连大学, 辽宁省生物有机化学重点实验室, 辽宁大连 116622
  • 收稿日期:2015-11-09 发布日期:2016-04-07
  • 通讯作者: 郑学仿 E-mail:dlxfzheng@126.com
  • 基金资助:
    国家自然科学基金(21571025, 21271036);辽宁省教育厅科学技术研究项目(L2013470, L2013471)

Mechanism of Oxymyoglobin Oxidation Reaction Induced by Ultraviolet Light

Hong-Yu CAO1,3,Ling-Xing GAO2,Qian TANG1,3,Jin-Hong SU2,Xue-Fang ZHENG1,2,3,*()   

  1. 1 College of Life Science and Biotechnology, Dalian University, Dalian 116622, Liaoning Province, P. R. China
    2 College of Environmental and Chemical Engineering, Dalian University, Dalian 116622, Liaoning Province, P. R. China
    3 Liaoning Key Laboratory of Bio-Organic Chemistry, Dalian University, Dalian 116622, Liaoning Province, P. R. China
  • Received:2015-11-09 Published:2016-04-07
  • Contact: Xue-Fang ZHENG E-mail:dlxfzheng@126.com
  • Supported by:
    the National Natural Science Foundation of China(21571025, 21271036);Science & Technology Project Department of Education, Liaoning Province, China(L2013470, L2013471)

摘要:

肌红蛋白通常在无光条件下可进行输氧、储氧等重要功能,实验中我们发现紫外光照射可促进氧合肌红蛋白(MbO2)的氧化反应,证实其在光照时部分生理功能会发生变化。紫外-可见(UV-Vis)吸收光谱数据显示,光照射时MbO2的Soret带最大吸收波长蓝移、Q吸收带544和580 nm处还原峰强度下降,说明紫外光光照促进O2解离, MbFe(Ⅱ)可被氧化至MbFe(Ⅲ)。四种波长光对光照氧化的影响程度为254 nm > 280 nm >430 nm > 409 nm;通入CO气体时氧合肌红蛋白较难发生光照氧化反应,即Fe的第六配位强度影响反应程度;溶液中的H+或OH-对光照氧化反应有促进作用; 254、280 nm波长光照射时,苯丙氨酸(Phe)、酪氨酸(Tyr)、色氨酸(Trp)三种游离氨基酸均促进光照氧化反应的进行,而409、430 nm波长光照射时三种游离氨基酸对光照氧化反应的影响较小。以上数据表明体内光诱导MbO2氧化反应过程中蛋白质内的Fe(Ⅱ)能否被光照激发形成未成对电子处于激发态是O2离去和二价铁被氧化的关键。

关键词: 氧合肌红蛋白, 紫外光, 游离氨基酸, 光照氧化, 光谱法

Abstract:

Myoglobin (Mb) achieves its biological functions such as oxygen transfer and storage in the dark. In this research, we found that UV light irradiation could promote oxidation of ferroporphyrin, which significantly affected the physiological function of oxymyoglobin (MbO2). The blue shift of the Soret band and decreased intensities of Q-band reduction peaks at 544 and 580 nm observed in UV-Vis absorption spectra revealed that UV light could promote O2 dissociation, and consequently MbFe(Ⅱ) was oxidized to MbFe(Ⅲ). The effect sequence of wavelength on the strength of this photo-oxidation was 254 nm > 280 nm > 430 nm > 409 nm. CO could inhibit the photo-oxidation process, indicating that the strength of the sixth coordination bond of Fe with a gas molecule influences the degree of photo-oxidation. The H+ and OH- in the solution could also promote the photo-oxidation process. Irradiated by 254 and 280 nm light, free amino acids phenylalanine (Phe), tyrosine (Tyr), and tryptophan (Trp) promoted the light oxidation reaction. Meanwhile, irradiation with 409 and 430 nm light had less influence on the UV-light-induced oxidation reaction under the same conditions. The results illustrated that in photo-induced oxidation of MbO2, the formation of an excited state of Fe(Ⅱ) with unpaired electrons upon irradiation is crucial process for O2 dissociation and Fe(Ⅱ) oxidation.

Key words: Oxymyoglobin, UV light, Free amino acid, Photo oxidation, Spectrometry

MSC2000: 

  • O641