In order to extract peptides from formalin-fixed tissue and compare the peptide profile differences between control group and disease group,different antigen retrieval(AR) methods were investigated in this paper: organic solvent,trypsin and magnetic bead.MALDI-TOF MS was used for evaluating the retrieval efficiency.Results showed: trypsin retrieval method was compatible to MS analysis and the higher quality spectra could be acquired,the time of digestion did not affect the peptide profile but the concentration was crucial.We concluded the optimal conditions as follows: digestion with 0.1μg/μL of trypsin at 37℃ for 2h and using the of α-cyano-4-hydroxy cinnamic acid as the MALDI matrix.
Saliva is a dilute solution of complex mixture containing proteins,glycoproteins,lipids and ions secreted from the major and minor salivary gland.In addition,the components of saliva are similar with that of blood.In this report,peptides and proteins in saliva were separated by magnetic beads and measured by MALDI-TOF-MS.The preparation method of salivary sample was standardized.
A protocol for serum peptidomics using peptide electrophoresis combining with mass spectrometry was reported in this paper.Results showed that the improved peptide electrophoresis and MALDI-TOF MS could evaluate the efficiency of serum peptide processing methods.Our protocol was verified with a high reproducibility.
