At low pH insulin is highly prone to self-assembly into amyloid fibrils. The process has been proposed to beaffected by the existence of secondary nucleation pathways, in which already formed fibrils are able to catalyzethe formation of new fibrils. In this work, we studied the fibrillation process of human insulin in a widerange of protein concentrations. Thioflavin T fluorescence was used for its ability to selectively detect amyloidfibrils, by mechanisms that involve the interaction between the dye and the accessible surface of the fibrils.Our results show that the rate of fibrillation and the Thioflavin T fluorescence intensity saturate at highprotein concentration and that, surprisingly, the two parameters are proportional to each other. BecauseThioflavin T fluorescence is likely to depend on the accessible surface of the fibrils, we suggest that theoverall fibrillation kinetics is mainly governed by the accessible surface, through secondary nucleationmechanisms. Moreover, a statistical study of the fibrillation kinetics suggests that the early stages of theprocess are affected by stochastic nucleation events.
|Numero di pagine||6|
|Rivista||JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL|
|Stato di pubblicazione||Published - 2008|
All Science Journal Classification (ASJC) codes