Fig. 4.

Analysis of amylin PEGylation reaction in aqueous solution. Amylin PEGylation was conducted in PBS, pH 7.4, as described in the “MATERIAL AND METHODS” section, in the presence of a 10:1 M ratio of mPEG/amylin, with mPEG-SC (a, c, e) or mPEG-SPA (b, d, f). The reaction was interrupted at the times indicated at the top of the gels and run on a 22.5% SDS-PAGE gel. a, b The gels were stained with Coomassie Brilliant Blue. The ladder (L) is composed of BSA (66 kDa), lysozyme (14 kDa), and insulin B-chain (3.4 kDa). c, d Densitometry analysis of the digitalized gel, as conducted with ImageJ. e, f The kinetics of the reaction, as followed by the integrated band area. The peaks were integrated with Fityk, and the relative area was plotted as a function of time. The details are described in the “MATERIAL AND METHODS” section