Mo W, Takao T, Shimonishi Y
Institute for Protein Research, Osaka University, Japan.
Rapid Commun Mass Spectrom. 1997;11(17):1829-34. doi: 10.1002/(SICI)1097-0231(199711)11:17<1829::AID-RCM81>3.0.CO;2-J.
Partial 18O-labeling of peptides has been applied to post-source decay experiments in a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer. The ions which originate from the carboxyl terminus of a peptide partially retain 18O atoms which have readily been incorporated into the C-terminal carboxyl groups during enzymatic hydrolysis in a buffer containing 40 atom percent H218O. The isotopic resolution of singly charged precursor ions and their product ions obtained for peptides up to ca. 2800 Da has been achieved using the delayed extraction method, which permits the rapid identification and assignment of the 18O-labeled and non-labeled ion species in the PSD spectra. The results obtained from several 18O-labeled peptides, derived from an enzymatic digest, demonstrate the accuracy and reproducibility of the present method, which will be in widespread use for protein identification via database searching or for investigations of totally unknown proteins.
肽的部分18O标记已应用于基质辅助激光解吸/电离飞行时间质谱仪中的源后衰变实验。源自肽羧基末端的离子部分保留了18O原子，这些原子在含有40原子百分比H218O的缓冲液中酶促水解期间很容易被并入C末端羧基中。使用延迟提取方法实现了对高达约2800 Da的肽的单电荷前体离子及其产物离子的同位素分辨率，该方法允许在PSD光谱中快速识别和区分18O标记和未标记的离子种类。从酶解消化得到的几种18O标记肽获得的结果证明了本方法的准确性和可重复性，该方法将广泛用于通过数据库搜索进行蛋白质鉴定或用于研究完全未知的蛋白质。
