Odorant-binding protein required for olfactory behavior and for activity of pheromone-sensitive neurons. Binds to alcohols and mediates avoidance behavior to high concentrations of alcohols, the alcohol-binding possibly resulting in activation of receptors on T2B neurons, the activation of these receptors inhibiting these neurons. Acts in concert with Snmp and lush to capture cVA molecules on the surface of Or67d expressing olfactory dendrites and facilitate their transfer to the odorant-receptor Orco complex. Required for cVA response, probably by binding to VA. May act by serving as an adapter that bridges the presence of gaseous pheromone molecules, cVA, to activation of specific neuronal receptors expressed on T1 olfactory neurons, possibly via a specific conformational change induced by cVA that in turn activates T1 receptors. T1 neurons are excited by the pheromone VA, while T2 neurons are inhibited by alcohols. Also binds to phthalates. Specifically expressed in chemosensory system in both males and females. Expressed in a subset of trichoid chemosensory sensilla located on the ventral-lateral surface of the third antennal segment. Secreted from non-neuronal support cells into the sensillum lymph that bathes the olfactory neurons within these sensilla. Belongs to the PBP/GOBP family. According to some authors (PubMed:14759510) it does not bind to ethanol. They suggest that the avoidance triggered by high concentration of alcohols may be due to impurities, such as phthalates or structurally related compounds, present as contaminants in the ethanol used. They conclude that it may be directly and strictly required for the perception of an odorant, rather than being involved only in modulating the response to ethanol.