A dissertation by Kang (2000) details results of OR-ligand assays for indole, Hedione, and naphthalene. The data show each molecule generating responses in a widespread, discontinuous, random-looking array of odorant receptors. Most of these receptors had not previously been deorphaned, and indeed assays typically suffer from some ORs failing to express on the cell surface […]

Françoise et al ([1], [2]) have identified OR2AG1 as a receptor associated with green pea, beany, grassy, galbanum, and bell pepper aroma characters of substituted pyrazines. This class of aroma compounds tends to have nutty, earthy, cacao, roasty, and potato type odors, and the compounds are almost all OR5K1 agonists (Marcinek et al, 2021), although […]

While it is believed that very few real world odors are “primary”, since neary every aroma compound would have multiple human olfactory receptors that are sensitive to it, empirical measurements of receptors’ responses to odors usually identify at most a handful of receptors, often as few as one or even zero. To compound the problem, […]

While aromas must certainly occupy a perceptual space, the dimensionality of this space remains mired in uncertainty. It has even been argued that the number of dimensions might equal the total number of olfactory receptors themselves! Conceivably, the perceptual space could be less than 400-dimensional, perhaps as little as 30-40 dimensions, if the various receptors […]