Figure 1

Identification and quantification of proteins by LC-MS/MS Based on SILAC method. (A) Clustering analysis of the identified proteins from L02 cells and HepG2 cells. Protein cluster map generated by Cluster software. Expression of proteins in the normal group was constant at 0, proteins up-regulated in cancer tissue were in red, and the down-regulated proteins were in green. The intensity of the color green or red corresponds to the degree of alteration, respectively, according to the color strip at the bottom of the figure. These data were derived from three independent analyses. (B) A total of 63 dysregulated proteins were classified into 11 groups with diverse functions including metabolism (34.9%), signal transduction (12.7%), structural component (7.9%), and other functions (44.5%). (C), (D), and (E) showed output of the LC MS/MS database using the MASCOT program. LC MS/MS analysis revealed 8 matched peptides with 38% sequence coverage and a MOWSE score of 172. The matched peptides were shown in bold red. (F), left, MS spectrum showed a SILAC peptide matching PGAM1, with an up-regulation up to 6-fold. The m/z presents a difference of 3 mass units between labeled and unlabeled peptide pair, resulting in a 2⁺ change state; right, control SILAC peptide from β-actin.