Inhibition of the formation
of IAPP amyloid by insulin. (A) The
results of thioflavin-T binding assays are displayed. The data are
plotted as time normalized by the T50 value
of IAPP in the absence of insulin: black, IAPP; red, IAPP and insulin
in a 20:1 ratio; green, IAPP and insulin in a 40:1 ratio; blue, IAPP
and insulin in a 60:1 ratio; pink, IAPP and insulin in an 80:1 ratio;
cyan, IAPP and insulin in a 100:1 ratio; brown, insulin alone at 0.8
μM. (B) TEM image of IAPP. (C) TEM image of a 20:1 mixture of
IAPP and insulin. IAPP is in 20-fold excess. (D) TEM image of insulin
alone at 0.8 μM. Aliquots were removed at the end of each reaction
for TEM analysis. Scale bars represent 100 nm. The kinetic experiments
were conducted in 20 mM Tris-HCl (pH 7.4) and 2% (v/v) HFIP without
stirring at 25 °C. The IAPP concentration was 16 μM.