Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/28/2009
Publication Date: 2/28/2009
Citation: Silva, C.J., Onisko, B.C., Dynin, I.A., Erickson, M.L., Carter, J.M. 2009. Quantifying prions in experimentally infected animals. [Abstract]. PrP Canada Navigating the Risks. Path 58. p81.
Technical Abstract: Prions and the normal cellular prion protein (PrPC) are isoforms. Prions are insoluble in non-denaturing detergents and pellet when subjected to ultracentrifugation. In contrast, PrPC does not pellet under these conditions. Most known prions are more resistant to proteinase K digestion than is PrPC. These properties make prion isolation straightforward. The analysis of prions is complicated by their heterogeneity. Prions are oligomers that are composed of a single protein containing highly variable post-translational modifications. The Foodborne Contaminants Research Unit uses mass spectrometry to quantify prions in experimentally infected animals. Our method is based on analyzing a characteristic trypsin-cleavage peptide. This peptide was selected for its empirically determined physical properties. It ionizes the best of all of the peptides resulting from trypsin cleavage. Our limit of detection for prions is in the attomole (10-18 mole) range. This approach can be used to quantitate both proteinase K sensitive and proteinase K resistant prions. It has been used to determine the quantity of prions present in the brains of naturally infected sheep, deer and elk.