Proton transfer to a charged dye bound to the alpha-chymotrypsin active site studied by laser photolysis.

Pulsed laser photolysis has been used to study the very rapid relaxation of the complex of alpha-chymotrypsin (EC 3.4.21.1) with the coloured inhibitor Biebrich Scarlet. The light absorption causes the dissociation of the proton in the dye naphthol ring and we are able to follow the recombination process under conditions of different ionic strength and pH. The recombination is markedly influenced by the pH around pH 7. The data suggest the existence of relevant interactions in the active site area between the hydrophobic binding site and the proton relay system of the enzyme.