Heme, as a chaperone, binds to amyloid fibrils and forms peroxidase in vitro: possible evidence on critical role of non-specific peroxidase activity in neurodegenerative disease onset/progression using the alpha-crystallin-based experimental system.

We report that heme not only displays high binding affinity to the aggregates of crystallin, but also it is effectively able to interfere with this type of aggregation. In the present study, the influence of heme concentration on the crystallin fibrillogenesis was also investigated and experimental evidence of heme's prevention of crystallin aggregation was provided with the help of spectroscopic measurements. Significantly, using alpha-crystallin-based experimental system, we proposed that elevated levels of peroxidase activity may have a determinant role in amyloid pathogenesis. The substantial peroxidase activity of "crystallin aggregate-heme" may partially explain the acceleration of oxidative damage in several amyloid-affected neurodegenerative diseases. The present study also suggests that lipid peroxidation accompanying amyloidogenesis may be considered as a major cause in the pathogenesis of amyloid disorders. Since the consequence of heme-amyloid interaction has yet to be identified, additional data on it may help us to manage amyloid aggregation processes.