[The effect of red pigment of Saccharomyces cerevisiae on insulin fibril formation in vitro].

The effect of the yeast red pigment, the result of polymerization of AIR, and of its low molecular weight derivative (presumably devoid of phosphoribosyl moiety) on the formation of amyloid fibrils in vitro was studied. Both the red pigment and its derivative, the result of acid hydrolysis of the original pigment, were shown to diminish the intensity of amyloid bound Thioflavine T fluorescence. Correlation between the decrease of the intensity of Thioflavine T fluorescence and the concentration of both forms of the red pigment was demonstrated. Both forms were also able to compete with Thioflavine T for amyloid fibrils. Electron microscopy permitted to visualize a drop of fibril size in the case of red pigments presence during their formation.