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Design and synthesis of novel inhibitors of prohormone convertases

1994; Wiley; Volume: 44; Issue: 3 Linguagem: Inglês

10.1111/j.1399-3011.1994.tb00168.x

0367-8377

Ajoy Basak, François Jean, Nabil G. Seidah, Claude Lazure,

Biochemical and Structural Characterization

Prohormone convertase‐1 (PC1) and furin are subtilisin‐like endopeptidases involved in the biosynthesis of peptide hormones. Five decapeptides representing the junction between the pro‐region and the catalytic region of PC1 were prepared. The core sequence corresponded to D‐Tyr‐Arg‐Ser‐Lys‐Arg‐Xaa‐Val‐Gln‐Lys‐Asp where D‐Tyr replaces the native Glu residue and Xaa, representing the P1′ position, corresponds to L‐Ser, L‐Leu or the unnatural amino acids, D‐Ser, β‐Ala, γ‐Abu, β‐Cha or γ‐Hyp. Another analog incorporating an Orn residue in place of the Arg at the P1 site was also prepared. These peptides, synthesized by solid‐phase Fmoc chemistry, were fully characterized by FAB‐MS, 1 H‐NMR and amino acid composition. Except for Orn, γ‐Hyp, L/D‐Ser and L‐Leu containing analogs, the others were found to be moderate to potent competitive inhibitors of hPCl activity in the following order: γ‐Abu>β‐Cha>β‐Ala, with K i values ranging from 1 to 8.6 μM. Both L‐Ser and L‐Leu analogs were correctly cleaved at the acyl carbon COOH‐terminal to the Lys‐Arg pair by human PCl, whereas β‐Cha, γ‐Abu, β‐Ala and D‐Ser analogs proved to be very poor substrates. The Orn and γ‐Hyp derivatives were not cleaved by the enzyme at all. The three analogs containing β‐Cha, γ‐Abu and β‐Ala also proved to be potent inhibitors of the human furin activity in the following order: β‐Ala>β‐Cha> γ‐Abu, with K 1 ranging from 0.8 to 2.2μM. Two more peptides, modified at the P1 position by addition of a semicarbazone (SC) moiety, were also synthesized by liquid‐phase chemistry. These peptides, Arg‐Ser‐Lys‐argininal‐SC and Arg‐Lys‐Lys‐argininal‐SC, also proved to be potent competitive inhibitors of hPCl and exhibited K i values 3.6 and 2.3 μM, respectively.