M. Elena Valera Mora, MD,
Antonino Scarfone, MD,
Menotti Calvani, MD,
Aldo V. Greco, MD and
Geltrude Mingrone, MD, PhD
Institute of Internal Medicine, Catholic University of Rome, Rome (M.E.V.M., A.S., A.V.G., G.M.), ITALY
Sigma Tau Pharmaceuticals, Pomezia (M.C.), ITALY
Fig. 1. The acidification of the endosomal lumen, due to the presence of proton pumps, results in dissociation of insulin from its receptor and the action of IDE leads to a production of multiple end-products.