  We examine the olfactory discrimination of left- and right-handed enantiomers
of chiral odorants based on the odorant-mediated electron transport from a
donor to an acceptor of the olfactory receptors embodied in a biological
environment. The chiral odorant is effectively described by an asymmetric
double-well potential whose minima are associated to the left- and right-handed
enantiomers. The introduced asymmetry is considered as an overall measure of
chiral interactions. The biological environment is conveniently modeled as a
bath of harmonic oscillators. The resulting Spin-Boson model is adapted by a
polaron transformation to derive the corresponding Born-Markov master equation
with which we obtain the elastic and inelastic electron tunneling rates. We
show that the inelastic tunneling through left- and right-handed enantiomers
occurs with different rates. The discrimination mechanism depends on the ratio
of tunneling frequency to localization frequency.
