Effect of red pigment on insulin fibril formation in vitro

The influence of red pigment isolated from yeast Saccharomyces cerevisiae and its low molecular weight derivate on insulin amyloid fibril formation in vitro was studied. The red pigment derivative, which presumably lacked phosphoribosyl moiety due to acid hydrolysis, retained the ability to inhibit fluorescence intensity (FI) of amyloid bound Thioflavine T. It was found that FI inhibition depended on the concentration of both pigment forms. Both forms were also able to compete with Thioflavine T for amyloid fibril binding. Electron microscopy revealed that fibrils reduced in size in the presence of red pigment.