The Exploration And Improvement Of The Identification Based On Tandem Mass(MS/MS) Spectra

With the development of mass-spectrometric technique,LC-MS/MS method of shotgun proteomics,gradually becomes one of the most commonly used technology.In practice,we treated the samples with the relevant enzymes to hydrolyze the peptides,and then took the peptide mixtures into mass spectrometry.The raw mass spectra obtained from LC-MS/MS required further analysis to determine what the peptides and proteins were in the sample,that was,the identification of the peptides and proteins.The existing identification approaches are almost based on the protein sequence database such as Mascot and X! Tandem.However,these methods have their own limitations,for example,they are very dependent on the sequence database,ignoring the difference between theoretical spectra and experimental spectra,and spectra identification rate of these methods is pretty low.In order to solve these problems,this paper explored the identification workflow of mass spectra,and made a detailed discussion on each step of the peptide identification process.It is hopeful that the readers will have a better comprehensive and imaginative understanding on the identification process,and this paper will give some inspiration to improve it.On the basis of the various steps of the identification process,this paper also presents a whole workflow of the identification,which is called SpectraMatch and is based on the known spectral library.Unlike the software based on the protein sequence,this workflow uses the known MS/MS spectra as the reference spectral library and then let the experimental spectra match with them.It is proved that the method proposed in this paper is in good agreement with the popular software(Mascot,MSPepSearch,OMSSA and X!Tandem)no matter from the peptide,protein and pathway aspects,which proves the reliability of the workflow and proves the correctness of the identification process discussed in this paper.At the same time,because SpectraMatch can easily change the.reference spectra library,so it.is more.flexible than the methods based on the protein sequence.