A putative lipophilic stimulant carrier protein commonly found in the taste and olfactory systems. A unique member of the pheromone-binding protein superfamily.

In chemosensory systems, a variety of lipophilic ligand-binding proteins have been found in saliva or nasal mucus. Lipophilic stimulants reach the receptor membrane, carried by these proteins. An acidic 14-kDa protein purified in the blowfly, Phormia regina, belongs to the insect pheromone-binding protein superfamily, but unlike other lipophilic ligand-binding proteins in insect or vertebrate chemosensory systems, it was distributed in both taste and olfactory organs. A similar protein was also isolated in Drosophila melanogaster. Considering their distributions, cDNA sequences and structural features, we concluded that these proteins belong to a unique subfamily whose members have convergently evolved for a common function required for both senses of taste and olfaction. By an electrophysiological experiment using antiserum, we also suggested that these proteins carry fragrant components of natural foods in taste systems as well as in olfactory systems.