MALDI-TOF-MS在奥曲肽结构分析中的应用

MALDI-TOF-MS determination of the structure of octreotide

目的:应用基质辅助激光解析电离飞行时间质谱(MALDI-TOF-MS)对奥曲肽进行结构确证分析。方法:采用二巯基苏糖醇还原奥曲肽二硫键,碘代乙酰胺(IAM)封闭还原奥曲肽中的巯基,测定还原前后及烷基化奥曲肽相对分子质量,并应用源后衰变(PSD)对其进行序列分析。结果:奥曲肽、还原奥曲肽和烷基化奥曲肽相对分子质量测定值分别为1019.25,1021.24,1135.38,与 PSD 测定的序列相同,均和理论值一致。结论:本方法可以较快速分析奥曲肽结构,是此类多肽结构确证的有效方法。

Objective： To determine the primary structure of octreotide by matrix - assisted laser desorption/ioniza- tion time - of - flight mass spectrometry （ MALDI - TOF - MS）. Method. The octreotide disulfide bond was reduced by dithioerythritol （DTI＇）, the reduced octreotide was alkylated by iodoacetamide （IAM）, the relative molecular mass of octreotide, reduced octreotide and alkylated octreotide were measured by MALDI - TOF - MS, and the amino acid sequence was de novo interpreted through post source decay （PSD） spectra. Results： The relative molecular mass of octreotide was 1019. 25, the reduced relative octreotide molecular mass was 1021.24, the relative molecular mass of alkylated octreotide was 1135. 38, all accorded with the theoretical values. The PSD sequencing also accorded with the theoretical sequences. Conclusion：The method can quickly and effectively analyze the structure of octreotide and similar peptides.