Biol. Pharm. Bull. 29(5) 927—932 (2006)

eases are fatal neurodegenerative disorders that include Creutzfeldt–Jakob disease and Gerstmann–Sträussler– Scheincker syndrome in humans, and scrapie, bovine spongiform encephalopathy and chronic wasting disease in animals. These disorders are characterized by accumulation in the brain of an abnormal isoform of prion protein (PrP), which includes a high beta-sheet content and is resistant to digestion with proteinase K. Recent outbreaks of variant Creutzfeldt–Jakob disease and iatrogenic Creutzfeldt–Jakob disease through use of cadaveric growth hormone or dura grafts in younger people have necessitated the development of suitable therapies. Compounds such as antimalarials and amyloid binding dyes are known to possess anti-prion activity in vitro or in vivo. Among them, Congo red and quinacrine are known to bind directly to PrP and thereby strongly inhibit proteinase K-resistant PrP (PrPres) formation. However, it remains unclear whether or not other anti-prion compounds and amyloid binding dyes interact directly with PrP. This study analyzed interactions of some previously reported anti-prion compounds and popularly used amyloid binding dyes with recombinant PrP using surface plasmon resonance (SPR). In addition, we evaluated whether SPR assay is useful as a screening tool for anti-prion compounds.