Endosomal acidic insulinase

Substrates for hepatic metabolism include insulin, glucagon, and t-PAs [89,90]. For insulin, an acidic endopeptidase (termed endosomal acidic insulinase ) appears to mediate internalized insulin proteolysis at a number of sites [91]. Specifically, the endosomal activity results from cathepsin D, an aspartic acid protease [92]. Similarly, proteolysis of glucagon has also been attributed to membrane-bound forms ofcathepsins B and D [93]. 

Authier, F., G.M. Danielsen, M. Kouach, G. Briand, and G. Chauvet. 2001. Identification of insulin domains important for binding to and degradation by endosomal acidic insulinase. Endocrinology 142 276-289. 

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