Cyclodextrin retinylidene: A biomimetic kinetic trap model for rhodopsin

All trans retinal was attached to both the primary face and the secondary face of β-cyclodextrin via a Schiff base linkage, analogous to that in rhodopsin. The new models were evaluated and compared with n-butylamine retinylidene Schiff base for their rates of hydrolysis, and factors that influence such rates. Competition studies using adamantane carboxylate demonstrated the kinetic trap theory by diminishing the binding of retinal in the cyclodextrin, thereby augmenting the rate of hydrolysis. NMR experiments indicate that the retinylidene is most probably bound in the form of a dimer.

Displacement of the β-ionone ring by adamantane carboxylate increases the rate of Schiff base hydrolysis.Figure optionsDownload as PowerPoint slide