Cyanoacrylate Inhibitors of the Hill Reaction IV. Binding Characteristics of the Hydrophobic Domain

Abstract

Aryl- and aralkyl-amino derivatives of 2-cyanoacrylic esters were synthesized and assayed as inhibitors of the Hill reaction in isolated pea chloroplast fragments. Aryl- and aralkyl-amino 2-cyanoacrylates unsubstituted in the β-position were weak inhibitors but activity could be greatly enhanced by inclusion of a β-alkyl group with the increase in potency being dependent on the carbon chain length of the β-substituent. The magnitude of this effect appeared independent of the nature of the aryl- or aralkyl-amino function. Inclusion of a carbon chain between the phenyl and amino functions of phenylamino-2-cyano- acrylates produced a stepwise increase in activity with increasing chain length, indicating a prefer- red orientation for the phenyl ring within the hydrophobic binding domain.