Jiao, Guan‐Sheng

The prohormone convertases PC1/3 and PC2 are eukaryotic serine proteases involved in proteolytic maturation of peptide hormone precursors and implicated in a variety of pathological conditions, including obesity, diabetes, and neurodegenerative diseases. In this work, we screened 45 compounds obtained by derivatization of a 2,5‐dideoxystreptamine scaffold. We found four promising PC1/3 competitive inhibitors and three PC2 inhibitors exhibiting various inhibition mechanisms with sub‐ and low micromolar inhibitory potency against a fluorogenic substrate. Low micromolar concentrations of certain compounds blocked the processing of the physiological substrate proglucagon. Interestingly, we identified compounds that were able to stimulate both 87 kDa PC1/3 and PC2 activity. Molecular modeling studies revealed interactions of the PC1/3 inhibitors with the active site that suggest structural modifications to further enhance potency. In support of experimental data suggesting that PC2 inhibition likely occurs via an allosteric mechanism, we identified several possible allosteric binding sites using computational searches. This work was supported by DA050854 to Iris Lindberg.