Location: Foodborne Contaminants Research
Title: Mass Spectrometric Approaches to Detecting and Quantifying Prions Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 31, 2008
Publication Date: March 31, 2008
Citation: Silva, C.J., Onisko, B.C., Dynin, I.A., Erickson, M.L., Carter, J.M. 2008. Mass Spectrometric Approaches to Detecting and Quantifying Prions. [Abstract]. Third International CWD Symposium. Advancing the Science and Developing the Tools. Vol 3. p23. Technical Abstract: Prions are infectious proteins that replicate by converting a normal cellular protein (PrPC)into a prion. Although prions and PrPC are isoforms, they have dramatically different physicochemical properties. Prions are resistant to proteinase K (PK) degradation, while PrPC is completely degraded by PK. PrPC is soluble in non-denaturing detergents, such as sarkosyl. In contrast, Prions are insoluble in such detergents. Ultracentrifugation can be used to separate prions from PrPC. The Foodborne Contaminants Research Unit has exploited these physicochemical properties to purify and analyze prions using mass spectrometry. This method is based on the detection of a characteristic trypsin-cleavage peptide found in hamster PrPC. This peptide ionizes the best of all of the peptides resulting from trypsin cleavage. The limit of detection for prions, using this method, is in the attomole (10-18 mole) range. This approach has been used to quantitate both proteinase K sensitive and proteinase K resistant hamster-adapted prion strains. An analogous peptide is present in PrPC from sheep, deer and cows. This peptide has been used to quantitate of prions present in the brains of naturally infected sheep.