3C-O2-1535（3P-42） PDF
Novel approaches to enrich protein terminal peptides for protein terminome analysis
Although the number of human protein-coding genes is estimated to be around 20,000 entities, it has also been estimated that the human genome is translated into 1 billion protein isoforms, arising from a single gene but existing in different sizes and amino acid compositions. Since the expression profiles of protein isoforms depend on cell types, tissues and disease status, and controlled by transcriptional and translational regulation, it is important to profile the N- and C-termini of each protein isoforms, called the protein terminome, to understand the cell functions. Shotgun proteomics has been employed to profile the expressed proteomes. Since the protein identification is based on the identification of the tryptic peptides derived from the protein, it is difficult to identify the protein isoforms in some cases, and the information of N- and C-termini of each protein isoform is inevitably required to conduct protein terminomics.
Here, we developed the novel enrichment methods for protein terminal peptides. For N-terminomics, α- and ε-amino groups of proteins were subjected to reductive dimethylation. After proteolysis, protein N-terminal peptides were enriched by subtracting internal peptides. In this presentation, we will also report the terminome analysis of whole cell lysates from human and other organisms.