MALDI质谱检测蛋白质与富勒醇的非共价复合物

基质辅助激光解吸电离(MALDI)质谱由于受到酸性基质、样品制备、激光诱导聚合和基质加合物的形成等条件的限制而难以用于非共价复合物的检测.本文以芥子酸为基质,观察到蛋白质与富勒醇的特殊相互作用,一些质谱特征,如质量数迁移、宽的加合峰和定量结合比表明,在蛋白质和富勒醇之间形成了特殊的非共价复合物.其中,血红蛋白与富勒醇的结合比是1:4,而肌红蛋白与富勒醇的结合比是1:1.实验结果表明:富勒醇可用来保护血红蛋白,有在酸性介质中防止其分解的作用.因此,通过在基质组份中添加特性有机化合物保护被测样品,有可能实现用MALDI质谱测定四级结构蛋白质的分子量.

Detection of Specific Noncovalent Protein-fullerenols Complexes by Matrix-assisted Laser Desorption Ionization Mass Spectrometry

Matrix assisted laser desorption ionization(MALDI) mass spectrometry is difficult for the characterization of noncovalent complexes hitherto because of the limitations in acidic matrix, sample preparation, laser induced polymerization and adduct formation with matrix. Under our experimental conditions, sinapinic acid is used as a matrix, the specific noncovalent interactions of protein with fullerenols were observed by MALDImass spectrometry. Some mass spectrometric features, such as mass shifts, broad adduct peaks and stoichiometries, showed that the specific non covalent complexes between protein and fullerenols have been formed at a ratio of 1:4 for hemoglobin fullerenols or 1:1 for myoglobin fullerenols. The results implied that fullereneols could be used to protect partly hemoglobin from decomposition in acidic media, and therefore, it is possible to realize the molecular weight determination of a quaternary protein by MALDImass spectrometry via the addition of specific organic compound in the matrix.