Lc-ms Proteomics Identification Of The Establishment Of The Normal Urinary Proteome Identification Applications

In this study we systematically studied tryptic peptides elution condition and the characteristics of identified peptides in reverse phase liquid chromatography and electrospray ion trap tandem mass spectrometry (LC/MS/MS) analysis. Following protein digestion with trypsin, the peptide mixture was analyzed by on-line LC/MS/MS. Bovine serum albumin (BSA) had been used to develop the proper ACN elution gradient for tryptic peptides and Cytochrome C was used to prove the gradient and the sensitivity of LC/MS/MS. In addition, the characteristics of identified peptides were analyzed. In our experiments, the suitable ACN gradient was 5% to 30% for tryptic peptides elution and the sensitivity of LC/MS/MS was 50 fmol. Analysis of the tryptic peptides demonstrated that longer (more than 10 amino acids) and +2 charge peptides are likely to be identified. Moreover, in this study the identified peptides present three types of redundancy: (1) identification redundancy: one peptide with one certain charge state can be repeatedly fragmented; (2) charge redundancy: one peptide may be identified with different charge states; (3) sequence redundancy: more than one peptide may be identified from one root sequence.