Identification of potential activators of proteinase-activated receptor-2

In order to identify physiological activators of proteinase-activated receptor-2 (PAR-2), a peptide chloromethane inhibitor (biotinyl-Ser-Lys-Gly-Arg-CH2Cl) based on the cleavage site for activation of PAR-2 was synthesised and tested with 12 trypsin-like serine proteinases, The second-order rate constant (k(i)/K-i) for the formation of the covalent proteinase-inhibitor complex varied by 2 x 10(5)-fold between the proteinases, Biotinyl-Ser-Lys-Gly-Arg-CH2Cl reacted very rapidly with trypsin, acrosin from sperm and tryptase from mast cells: the k(i)/K-i values with these proteinases were greater than 10(5) M-1. s(-1). Thus, the specificity of these proteinases matched the sequence of the activation site of PAR-2 and it can be concluded that these proteinases are potential physiological activators of PAR-2. (C) 1997 Federation of European Biochemical Societies.