Loo J A, Udseth H R, Smith R D
Chemical Sciences Department, Pacific Northwest Laboratory, Richland, Washington 99352.
Anal Biochem. 1989 Jun;179(2):404-12. doi: 10.1016/0003-2697(89)90153-x.
The extension of mass spectrometry to high molecular weight biopolymers based upon electrospray ionization and the on-line combination with capillary electrophoresis is described. Electrospray ionization produces gas-phase intact multiply charged molecular ions of biomolecules from highly charged liquid droplets by a high electric field. For high molecular weight substances electrospray ionization results in a characteristic bell-shaped distribution of multiply charged ions, with each adjacent major peak in the spectrum differing by one charge. Multiply charged molecular ions of proteins with molecular weights greater than 130,000 have been observed with a quadrupole mass spectrometer of limited mass-to-charge range (m/z 1700). Molecular weights can be readily determined for large proteins with accuracies in the range of +/- 0.01 to 0.05%; at least an order of magnitude further improvement appears feasible with improved techniques and instrumentation. The electrospray ionization method is sensitive, presently requiring samples in the 100 fmol to 10 pmol range for proteins. Initial results combining rapid separations by capillary zone electrophoresis with on-line mass spectrometric detection via the electrospray ionization source are demonstrated for myoglobin and other proteins and polypeptides. The potential for extension of these methods to molecular weights on the order of 10(6) is discussed.
本文描述了基于电喷雾电离以及与毛细管电泳在线联用，将质谱技术扩展至高分子量生物聚合物的方法。电喷雾电离通过高电场从高电荷液滴中产生生物分子的气相完整多电荷分子离子。对于高分子量物质，电喷雾电离会产生多电荷离子的特征钟形分布，光谱中相邻的每个主峰相差一个电荷。使用质量电荷比范围有限（m/z 1700）的四极杆质谱仪已观察到分子量大于130,000的蛋白质的多电荷分子离子。对于大蛋白质，分子量可以很容易地确定，准确度在±0.01%至0.05%范围内；随着技术和仪器的改进，至少再提高一个数量级似乎是可行的。电喷雾电离方法很灵敏，目前蛋白质样品需要100飞摩尔至10皮摩尔的范围。展示了通过毛细管区带电泳进行快速分离并通过电喷雾电离源进行在线质谱检测相结合的初步结果，检测对象为肌红蛋白以及其他蛋白质和多肽。还讨论了将这些方法扩展至分子量约为10⁶的潜力。
