Research Of Quality Control Methods Based On The Large-scale Mass Spectrum Data About Protein Identification

Human Genome Project(HGP)was completed in 2005.The success in decoding the human sequence and genomic mapping deeply inspired scientists to decipher the mystery of science including the law of childbirth,old age,sickness and funerals,the origin of life and evolution process and the underlying cause of individual difference.To better understand and master the essence and rule of life,researchers focused their study on proteomics which directly affect vital movement and biological process.Bio-mass spectrometry(bio-ms)is the critical supporting technology.The leap in technology of bio-ms greatly promoted proteomics development and thus research enter the era of large-scale proteomics.Various peptides form a protein.A peptide can only be acquired when a fragmentation ions spectrum is successfully matched with a standard spectrum embodied in protein sequence database.The combination of bio-ms technology and database searching approaches contributed to the accumulation of multiple high-throughput mass spectrometric data of proteomics.However,although the database searching approaches enhance the efficiency of protein identification,protein quality remains a thorny issue due to the sample difference,performance difference of various categories of mass spectrometers,deficiency of database searching algorithm and artificial factors during the experiment.Thus,the research objective is to give consideration to the number and the accuracy of identified protein,namely improve the recall rate while reduce false positive.Quality control method is the key issue to be resolved.The research focal point of the thesis is to establish quality control method of protein identification for large-scale protein mass spectrometry data from different sources and reduce false positive.We downloaded the protein mass spectrometry of saccharomyces cerevisiae from 113 raw files in proteomexchange.The proteins were fused by four different instruments.We introduced weight-marked quality control method to identify proteins.Comparison among traditional method which filters the'spectrometry,regular method which filters proteins based on scores indicated and our new method indicated that the regular one superior to the traditional one and moreover,our new method can certainly improve the quality control results.