Method for the Sample Handling and Analysis of Bio-Active Peptides

摘要

A method has been developed for the sample handling and analysis of bio-active peptides. Based on electrospray ionization mass spectrometry (ESI-MS) , the method is applicable to the target analysis of known peptides. ESI-MS is used to determine the molecular mass of the peptide and provisional identification is based on matching the molecular mass with that of known peptides in a database. Disulfide bridge reductive alkylation is used to determine the number of cysteines in the peptide as well as the presence of disulfide bridges. The peptide is then enzymatically digested and the digestion products analyzed by ESI-MS. The resulting mass map is compared to the masses predicted from the structure of the peptide. Finally, the peptide and its enzymatic fragments are analyzed by liquid chromatography (LC) ESI-MS using collisional activated disassociation (CAD) conditions which promote the formation of product ions from which it is possible to determine the amino acid sequence of the peptide. The developed method was applied to the analysis and identification of alpha-conotoxin GI.