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Updated: Aug 17, 2026

Real-time In Vitro Monitoring of Odorant Receptor Activation by an Odorant in the Vapor Phase
Published on: April 23, 2019
Odorant binding initially occurring at the central pocket in bovine odorant-binding protein
Mineo Ikematsu1, Daizo Takaoka, Masashi Yasuda
1Human Ecology Research Center, Sanyo Electric Co., Ltd., 1-1-1 Sakata, Oizumi, Ora, Gunma 370-0596, Japan. mikematsu@rd.sanyo.co.jp
Abstract:
Why bovine odorant-binding protein (OBPb), among OBP family, assumes a dimeric structure has been unclear. Here we clarified, by measuring the fluorescence of intrinsic tryptophan and tyrosine residues of intact OBPb and OBPb whose C-terminal 10 amino acids were deleted, that odorant enters the central pocket formed by the dimerization when OBPb first encounters odorant, and odorant with high affinity with OBPb subsequently enters the internal cavity (suggested binding site), releasing the pre-bound odorant. The internal cavity-bound odorant can be released by the binding of other odorants at another internal cavity or at the central pocket, depending on the binding odorants. Due to this mechanism enabled by the dimerization, OBPb is more reactive than other monomeric OBPs.
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