The Wistar Institute Proteomics Facility

The Wistar Institute Proteomics Facility provides mass spectrometry (MS) and sequence analysis of proteins and peptides at maximum sensitivity using state-of-the-art instruments and methods.

The most commonly used services are identifications of either purified proteins or complex protein mixtures, such as sub-proteomes or complete proteomes, using electrospray ionization tandem mass spectrometry (ESI MS/MS). Typically, either individual bands are excised from 1-D SDS gels, or the entire gel lane is analyzed by slicing it into uniform fractions followed by trypsin digestion and nanocapillary HPLC interfaced directly with hybrid ion trap mass spectrometry (Gel/LC-MS/MS). Data is analyzed and filtered to produce low false-positive rates. Several options are available for quantitatively comparing protein changes in related samples, and additional options will be implemented in the future.

Complementary services include reverse-phase microbore HPLC peptide mapping with UV detection and mass measurements of intact peptides and proteins using MALDI MS or ESI MS. Posttranslational modification (PTM) analyses including identifications of specific modified residues also are provided, although investigators should recognize that in most cases these studies are quite complex and require substantial effort. These studies, as well as analyses of complex protein mixtures, usually require preparation of custom sequence databases and/or custom data analyses, which can be provided by the facility as needed.