Department of Chemistry, University of California, Berkeley, California 94720-1460, United States.
Anal Chem. 2011 Mar 15;83(6):2210-4. doi: 10.1021/ac1031012. Epub 2011 Feb 21.
A solution additive has been discovered that can be used to measure the number of basic sites in a peptide or protein using electrospray ionization (ESI) mass spectrometry. Addition of millimolar amounts of perchloric acid (HClO(4)) to aqueous solutions that contain peptides or proteins results in the noncovalent adduction of HClO(4) molecules to the multiply charged ions formed by ESI. For 18 oligopeptides and proteins, ranging in molecular weight from 0.5 to 18.3 kDa, the sum of the number of protons plus maximum number of HClO(4) molecules adducted to the lower charge state ions is equal to the number of basic sites in the molecule. This method provides a rapid means of obtaining information about the composition of a peptide or protein and does not require high-resolution measurements or any instrumental or experimental modifications.
现已发现一种溶液添加剂，可用于使用电喷雾电离 (ESI) 质谱法测定肽或蛋白质中的碱性基团数量。在含有肽或蛋白质的水溶液中添加毫摩尔浓度的高氯酸 (HClO(4)) 会导致 HClO(4)分子非共价地加合到 ESI 形成的多电荷离子上。对于分子量在 0.5 至 18.3 kDa 之间的 18 个寡肽和蛋白质，质子数加上与低电荷状态离子加合的最大 HClO(4)分子数的总和等于分子中的碱性基团数量。该方法提供了一种快速获取肽或蛋白质组成信息的方法，不需要高分辨率测量或任何仪器或实验修改。
