title: Novel insights into amylin aggregation.
abstract: Amylin is a peptide that aggregates into species that are toxic to pancreatic beta cells, leading to type II diabetes. This study has for the first time quantified amylin association and dissociation kinetics (association constant (ka) = 28.7 ± 5.1 L mol-1s-1and dissociation constant (kd) = 2.8 ± 0.6 ×10-4s-1) using surface plasmon resonance (SPR). Thus far, techniques used for the sizing of amylin aggregates do not cater for the real-time monitoring of unconstrained amylin in solution. In this regard we evaluated recently innovated nanoparticle tracking analysis (NTA). In addition, both SPR and NTA were used to study the effect of previously synthesized amylin derivatives on amylin aggregation and to evaluate their potential as a cell-free system for screening potential inhibitors of amylin-mediated cytotoxicity. Results obtained from NTA highlighted a predominance of 100-300 nm amylin aggregates and correlation to previously published cytotoxicity results suggests the toxic species of amylin to be 200-300 nm in size. The results seem to indicate that NTA has potential as a new technique to monitor the aggregation potential of amyloid peptides in solution and also to screen potential inhibitors of amylin-mediated cytotoxicity.
authors.affiliation: Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal , Durban , South Africa.
authors.forename: Karen
authors.initials: K
authors.lastname: Pillay
authors.affiliation: Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal , Durban , South Africa.
authors.forename: Patrick
authors.initials: P
authors.lastname: Govender
keywords: amylin; nanoparticle tracking analysis; surface plasmon resonance; type II diabetes