反应体系pH对聚乙二醇牛血红蛋白偶联物性质的影响  

Effect of pH value of reaction system on properties of pegylated bovine hemoglobin conjugate

作　　者：常琛 尤国兴 王巍[2] 李伟丹 王瑛 朱凯 周虹 赵莲 陈玉芝 CHANG Chen;YOU Guoxing;WANG Wei;LI Weidan;WANG Ying;ZHU Kai;ZHOU Hong;ZHAO Lian;CHEN Yuzhi(Academy of Military Medical Sciences,Academy of Military Sciences,Beijing 100850,China;The Fourth Medical Center,Chinese PLA General Hospital,Beijing 100089,China)

机构地区：[1]军事科学院军事医学研究院,北京100850 [2]解放军总医院第四医学中心,北京100089

出　　处：《军事医学》2024年第10期753-759,共7页Military Medical Sciences

摘　　要：目的探究反应体系pH对醛基化聚乙二醇(PEG)修饰牛血红蛋白(bHb)偶联物性质的影响。方法设置反应体系的pH值分别为6.0、6.5、7.4和8.0,保持投料摩尔比、温度和反应时间相同,分别合成PEG-bHb,表征PEG-bHb的结构及功能参数。结果高铁血红蛋白百分含量随反应体系pH值的上升而下降;反应体系为弱酸性时,PEG-bHb的修饰度相对较高,当反应体系pH为6.5时,bHb表面连接PEG链的平均个数为(6.86±0.38)个;反应体系为弱酸性时,PEG对bHb N端α-NH_(2)的选择性修饰相对较强,当反应体系pH为6.5时,醛基化PEG对bHb的N端α-NH_(2)的修饰百分比达到95.4%(α链)和99.3%(β链);PEG修饰影响bHb血红素区域微环境,当反应体系pH为6.5时,PEG修饰对bHb结构的影响相对较低;PEG修饰后,PEG-bHb的氧亲和力升高,Hill系数下降,胶体渗透压和黏度升高,粒径增大,与bHb组相比,差异具有统计学意义(P<0.001)。结论反应体系pH为弱酸性环境时,PEG对bHb N端α-NH_(2)的选择性修饰百分比及修饰度相对较高。Objective To explore the impact of pH value of the reaction system on the properties of bovine hemoglobin modified with aldehydeated polyethylene glycol(PEG-bHb).Methods PEG-bHb conjugates were synthesized under varying pH conditions(6.0,6.5,7.4 and 8.0)of the reaction system while consistent molar ratios,temperature,and reaction time were maintained.The structural and functional attributes of PEG-bHb were characterized.Results The proportion of methemoglobin decreased with an increase in pH.In a weakly acidic reaction environment,the PEG-bHb was found to be relatively highly modified.At pH 6.5,the average number of PEG chains attached to the bHb surface was 6.86±0.38.Selective PEG modification of the N-terminal α-NH_(2) groups was more pronounced under weakly acidic conditions.Specifically,at pH 6.5,the modification efficiency of the N-terminalα-NH_(2) groups of bHb by aldehyde-activated PEG reached 95.4% for theα-chains and 99.3% for the β-chains.The PEG modification influenced the heme region microenvironment of bHb,with minimal structural impact observed at pH 6.5.After modification,the oxygen affinity of PEG-bHb was enhanced,the Hill coefficient was reduced,and there were significant increases in colloid osmotic pressure,viscosity,and particle size,all of which differed markedly from the unmodified bHb group(P<0.001).Conclusion The synthesis of PEG-bHb under weakly acidic conditions can result in a high degree of selective modification of the N-terminalα-NH_(2) groups and an overall high degree of modification.

关 键 词：红细胞代用品 聚乙二醇 牛血红蛋白 选择性修饰 

分 类 号：R331.14[医药卫生—人体生理学]