Azobenzene-Containing, Peptidyl α-Ketoesters as Photobiological Switches of α-Chymotrypsin

Three photoswitchable, peptidomimetic inhibitors of α-chymotrypsin have been synthesised. The compounds comprise an azobenzene, an α-ketoester and l-phenylalanine. The compounds were photoisomerised to give enriched states of the (E) and (Z) isomers and these states were assayed against α-chymotrypsin. The inhibitors were shown to be moderately active with switching ability of between two- and three-fold between the two isomer-enriched states. The behaviour of the inhibitors in solution was examined; specifically, their hydration and configurational stability.