Quantitative proteomics

Currently the most common techniques used for protein identification and quantitation by LC/MS/MS for complex samples are generally divided into the two categories: labeled and label-free approaches. We offer both types of services summarized below:

 

Method

Category

Multiplex

Features

Main limitation

SILAC Labeled 3 Most accurate, MS-based quantitation Requires cell culture for labeling
Dimethyl Labeled 3 MS-based quantitation suitable for limited materials; flexibility Limit for 3-plex
iTRAQ Labeled 4 or 8 Excellent MS/MS-based quantitation; flexibility Ratio compression
TMT Labeled 6 or 10 Excellent MS/MS-based quantitation; flexibility Ratio compression
XIC Label-free 1 MS-based precursor ion intensities or peak areas Large quantitation variation, needs optimized LC
Spectral counting or emPAI Label-free 1 MS/MS-based spectra counts or pep ID numbers Large quantitation variation, needs optimized LC
SRM Label-free 1 Super-accurate MS/MS quantitation Requires synthesis of standard peptides and known targeted peptides

In addition, we provide equipment and software support for 2D gel-based quantitation analysis (2-DE or 2-D DIGE), upon requested for some specific projects.