- Proinsulin processing by the subtilisin-related proprotein convertases furin, PC2, and PC3. Smeekens, S.P., Montag, A.G., Thomas, G., Albiges-Rizo, C., Carroll, R., Benig, M., Phillips, L.A., Martin, S., Ohagi, S., Gardner, P. Proc. Natl. Acad. Sci. U.S.A. (1992)