Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (4): 872-878.doi: 10.3866/PKU.WHXB201601046

• ARTICLE • Previous Articles     Next Articles

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)

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