Proteomic Labeling Method Yields Only One Peptide per Protein
- *Abstract
-
Dr. Samie Jaffrey in the Pharmacology Department of the Weill Medical College of Cornell University has developed a way to determine the proteins present in complex protein mixtures, such as human biological fluids, using mass spectrometry. The sample to be analyzed is first treated with a reagent that introduces a capturable tag only on the C-terminus of the proteins in the sample. Treatment with a protease or other reproducible cleavage agent generates a set of labeled peptides that can be isolated from the complex cleavage mixture for mass spec analysis. Each of these isolated peptides is derived only from the C-terminus of the proteins. This treatment reduces the complexity of the mixture to only one peptide for each protein in the original sample, a complexity within the limits of conventional electrospray mass spec equipment, even for human samples. ICAT reagents, which label all cysteine-containing peptides, result in considerably more complex peptide mixtures.
Surprisingly, a transpeptidase enzyme catalyzes the C-terminus tagging reaction and the tag can be made in two forms which differ only by the isotope it carries at specific structural positions. Then, by individually tagging two samples to be compared -- one with the heavy isotope tag and the other with the light one -- and then mixing them, quantitative differences between the components in the two samples can be quickly and directly identified from these isotopic differences.
- *Licensing
- Dan-Oscar Antsonda429@cornell.edu212-746-1297
- 其他
-
None
- 國家/地區
- 美國
