Synthesis and evaluation of the sunflower derived trypsin inhibitor as a potent inhibitor of the type II transmembrane serine protease, matriptase

We report here the synthesis of a 14-amino acid long bicyclic peptide, prev iously isolated from sunflower seeds. This peptide, termed sunflower trypsi n inhibitor (SFTI-1), is one of the most potent naturally occurring small-m olecule trypsin inhibitors. In addition to inhibiting trypsin, the syntheti c SFTI-1 is also a very potent inhibitor, with a K-i of 0.92 nM, of the rec ently identified epithelial serine protease, termed 'matriptase'. Published by Elsevier Science Ltd.