Tyrosyl radical in haemoglobin and haptoglobin-haemoglobin complex: how does haptoglobin make haemoglobin less toxic?
Dimitri A.Svistunenko1
Andreea Manole2
1.Biomedical EPR Facility, School of Life Sciences, University of Essex, Colchester, Essex CO4 3SQ, UK2.Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
摘要：One of the difficulties in creating a blood substitute on the basis of human haemoglobin (Hb) is the toxic nature of Hb when it is outside the safe environment of the red blood cells.The plasma protein haptoglobin (Hp) takes care of the Hb physiologically leaked into the plasma-it binds Hb and makes it much less toxic while retaining the Hb's high oxygen transporting capacity.We used Electron Paramagnetic Resonance (EPR) spectroscopy to show that the protein bound radical induced by H2O2 in Hb and Hp-Hb complex is formed on the same tyrosine residue(s),but,in the complex,the radical is found in a more hydrophobic environment and decays slower than in unbound Hb,thus mitigating its oxidative capacity.The data obtained in this study might set new directions in engineering blood substitutes for transfusion that would have the oxygen transporting efficiency typical of Hb,but which would be non-toxic.
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分类号：R457.1(治疗学)
论文发表日期：2020-07-30
在线出版日期：2025-08-15（本平台首次上网日期，不代表文献的发表时间）
页数：11( 281-291 )
英文信息