Identification Of Endogenous Peptides Based On Mass Spectral Network

Endogenous polypeptides are natural biologically active peptides present in organisms,where endogenous neuropeptides can trigger key signaling responses of various endocrine functions,such as weight balance,pain sensation,and mental illness.Current analogues of glucagon-like peptide 1(GLP-1)are being used to treat metabolic diseases.Therefore,discovering new endogenous polypeptides in tissues and studying endogenous peptides for drug development and disease treatment has a great effect.The current mainstream methods for peptide identification are still mass spectrometry and database search methods.However,these two method are not ideal for the identification of endogenous polypeptides.At the same time,because of the complexity and diversity of post-translational modifications(PTMs)of peptides,database search methods cannot identify peptides with PTMs.Therefore,the development of better methods to improve the identification efficiency and sensitivity of endogenous peptides can play an important role in promoting the development of biomedicine.The main work is as follows:1.Analysis the disadvantages of mass spectrometry and database search methods,Trypsin will reduce the biological activity of endogenous peptide samples,making the quality of endogenous peptides extracted by mass spectrometry unsatisfactory.Proposed the spectral archive search method,the rat mass spectrometry data,which were not identified in public databases,were selected to identify endogenous neuropeptides in rats.2.The spectral networks method clusers mass spectrometry by calculating similarity cluster,and then uses mass spectral alignments to identify amino acid sequences or(post translational modifications)PTMs.Calculating the similarity of the mass spectrometry allows partial matching of the peptides and allows independent analysis of each mass spectrum of a particular peptide segment.Therefore,in this study,spectral networks method was used to analyze endogenous peptides,and unrecognized mass spectrometry resolved the neuropeptides and their correspondences PTMs information.Thirty-three endogenous peptides and corresponding eleven PTMs from mouse hypothalamic tissue were successfully resolved.This paper aims at the analysis of mass spectrometry,analyzes the existing methods and establishes peptides for the search process of spectrogram database,uses the results of spectra library search,and designs a spectra networks method to identify PTMs of peptides.Through the database search verification,the accuracy and validity of the identification results were determined,which provided a reference for the identification of mass spectra and complex PTMs in peptidomics.