SELECTION OF TRYPSIN-INHIBITORS IN PHAGE PEPTIDE LIBRARY

The newly developed techniques of peptide libraries have become a conv entional and efficient method in screening ligands of proteins of inte rest. We present here the successful results of selection of trypsin i nhibitors in a phage hexapeptide library. After affinity selection and activity assay, peptide sequences, deduced front DNA sequencing of th e phage peptides with the most striking trypsin activity, share some c ommon features with trypsin inhibitors reported. All of the phage pept ides selected out and those native and synthetic trypsin inhibitors re ported are composed of three parts: (a) positively charged part (Arg, Lys or their analogs); (b) polar parr that may form hydrogen bonds wit h Ser in the active site of trypsin; (c) hydrophobic part that interac ts with the nonpolar region of trypsin active site. (C) 1996 Academic Press, Inc.