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. 2009. Mass Spectrometric Approaches to Detecting and Quantifying Prions. [Abstract]. PrP Canada p28.
Technical Abstract: Until recently, the use of mass spectrometry has been limited to identifying covalent posttranslational modifications of PrPSc and PrPC. These efforts support the hypothesis that PrPC and PrPSc possess identical covalent posttranslational modifications. Technical advances in instrumentation now allow researchers to explore the chemistry of prions while using much less tissue. Our unit has developed methods to work on inactivated prions and still obtain relevant chemical information. We have examined the role modified amino acids (citrulline, oxidized methionine, and oxidized cysteine) play in PrPC and PrPSc chemistry. Our group has used mass spectrometry to quantify prions in experimentally infected animals. This approach is based on measuring the amount of a specific trypsin fragment of the PrP protein and allows us to detect prions in the attomole (10-18 mole) range. Our results show that mass spectrometric detection has comparable sensitivity to bioassay in hamsters. It can be used to quantitate both PK sensitive and PK resistant forms of PrPSc. Our approach can be used to quantitate the prions present in the brains of naturally infected sheep, deer and elk. Unlike antibody tests, mass spectrometry simultaneously identifies and quantitates a selected analyte.