Protein Science, Vol 1, Issue 10 1343-1352, Copyright © 1992 by Cold Spring Harbor Laboratory Press

ARTICLE

Purification and properties of the cellular prion protein from Syrian hamster brain

K. M. PAN, N. STAHL and S. B. PRUSINER
Department of Neurology, University of California, San Francisco, California 94143

The cellular prion protein (PrP(C)) is encoded by a chromosomal gene, and its scrapie isoform (PrP(Sc)) features in all aspects of the prion diseases. Prior to the studies reported here, purification of PrP(C) has only been accomplished using immunoaffinity chromatography yielding small amounts of protein. Brain homogenates contain two PrP(C) forms designated PrP(C)-I and -II. These proteins were purified from a microsomal fraction by detergent extraction and separated by immobilized Cu(2+) ion affinity chromatography. PrP(C)-II appears to be generated from PrP(C)-I by limited proteolysis of the N-terminus. Fractions enriched for PrP(C)-I were purified further by cation-exchange chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Greater than 90% of the final product migrated as a broad band of M(r) 33-35 kDa as judged by silver staining after SDS-PAGE. Digestion of PrP(C)-I with peptide-N-glycosidase (PNGase) compressed the band and shifted its mobility giving an M(r) of 27 kDa. The protocol described should be amenable to large-scale preparation of PrP(C), enabling physical comparisons of PrP(C) and PrP(Sc).
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