纳升电喷雾串联质谱在修饰多肽及未知多肽结构分析中的应用

Applications of nanoelectrospray tandem mass spectrometry in structure analysis of modified and unknown peptides

目的：以2种多肽为例，说明纳升电喷雾串联质谱存修饰多肽及未知多肽结构一级结构确证和分析中的应用。方法：存纳升电喷雾串联质谱TOF MS模式下对2种多肽的分子量进行了确认，然后在MS／MS模式下获得双电倚肽段的碎片离子峰。结果：曲谱瑞林一级结构全序列是E’HWSYWLRPG’，其中N-端焦谷氨酸和C-端甘氨酰胺。未知多肽通过“序列拼接法”得到该样品的全序列T’VSP^＊VWLPPSVY，其中第4位脯氨酸加合了一个钠离子，且N-端苏氨酸磷酸化。结论：本研究表明纳升电喷雾串联质谱在分析修饰多肽及未知多肽方面具有明显优势。

Objective：The application of nanoelectrospray tandem mass spectrometry in characterize and analysis of the primary structure of modified and unknown polypeptides, is expleined by example of 2 polypeptides. Methods： The molecular weights of two peptides were determined in TOF MS mode. Then fragmentation ions of [ M ＋ 2H ]^2＋ ion extracted from the nanoelectrospray tandem mass spectrometry（MS/MS） were subsequently obtained. Results： The primary structure of triptorelin is determined to be E＇HWSYWLRPG＇,of which the N - terminal is pyroglutamic acid （E＇） and the C - termianl is glycinamide （G＇）. The primary structure of unknown peptide was identified to be T＇VSP^＊ VWLPPSVY by sequence docking method, of which the N - terminal of the peptide, threonine （T＇） was phos-phorylated and the proline （fouth position）is conjugated with sodium ion （P^＊ ）. Conclution： The data suggested that eleetrospray tandem mass spectrometry technique have obvious advantage in analyzing the full sequence of modified or unknown peptides.