Rapid Odorant Release in Mammalian Odour Binding Proteins Facilitates Their Temporal Coupling to Odorant Signals

We have measured the effect of rat odorant-binding protein 1 on the rates of ligand uptake and liquid-to-air transfer rates with a set of defined odorous compounds. Comparison of observed rate constants (kobs) with data simulated over a wide range of different kinetic and thermodynamic regimes shows that the data do not agree with the previously held view of a slow off-rate regime (koff < 0.0004 s− 1). We propose that a rapid koff would be a necessary requirement for such a system, since slow odorant-release rates would result in significant decorrelation between the olfactory world and odour perception.