Odorant-binding protein as active ingredient for fragrance release regulated by sweat

Abstract

Mammalian odorant-binding proteins (OBPs) represent a fascinating class of small, soluble proteins that transport odors from the air to the olfactory receptors, through the nasal mucus. OBPs can accommodate diverse odorant molecules through their flexible binding pockets, undergoing conformational changes upon ligand binding. Acknowledge of release mechanism could be very useful to provide a controllable release trigger for cosmetic applications. However, OBPs face significant challenges when applied to keratin-based substrates (hair and wool) because OBPs demonstrate weak binding affinity to keratin. To overcome this challenge, pig OBP sequence was fused to keratin-binding peptide (KP) with a spacer (GQ20), designated as OBP::GQ20::KP. Protein structure revealed a high stability and high protein affinity to a ligand model (dissociation constants of 0.20 ± 0.04 M at 25 °C, 0.25 ± 0.03 M at 37 °C). However, when added a sweat solution, the dissociation constants decrease drastically (1.69 ± 0.01 M at 25 °C, 2.04 ± 0.02 M at 37 °C) what didn't happen tested with individual components of sweat. To understand the OBP::GQ20::KP functionality in cosmetic formulations, it was added to a body cream and a hair mask. Commercial products containing OBP::GQ20::KP, when in the presence of sweat, promoted an increase of 90.7% linalool release existent in body cream, and an increase of 77.0% linalool release present in hair mask, versus absence of this OBP in the same cosmetics (GCMS analysis). Olfactory assessment using volunteers supported OBP::GQ20::KP capacity to management of fragrances in response to human sweat.