Design and synthesis of redox stable analogues of sunflower trypsin inhibitors (SFTI-1) on solid support, potent inhibitors of matriptase.

[structure: see text] Matriptase is a member of the emerging class of type II transmembrane serine proteases. It was found that the sunflower trypsin inhibitor (SFTI-1), isolated from sunflower seeds, inhibits matriptase with a subnanomolar Ki of 0.92 nM. On the basis of this result, we designed and synthesized its proteolytically stable analogues, SFTI-2 and SFTI-3. SFTI-3 exhibited very good binding affinity to matriptase, and it was metabolically stable.