Fig 1. Chemical Structure of Sunflower Trypsin Inhibitor-1 and the “HC” Synthetic Strategy.

Chemical structure of native SFTI (A) and the synthetic strategy for “HC” analogue synthesis (B) are shown. Amino acid residues and their position in the native peptide sequence are labelled in letters and numbers respectively. The P1 residue which will fit into the enzyme substrate binding pocket is lysine located at position 5 with the scissile bond indicated by an arrow. The side of SFTI-1 that forms direct contact with the enzyme and the non-contacting side are segregated by the red line.