Odor degrading enzymes function

Figure 14.1 Schematic of olfactory sensillum and a generalized biochemical pathway of odor reception. A An olfactory sensillum includes 2-3 neurons surrounded by 3 support cells olfactory dendrites/cilia project up the fluid filled lumen of a cuticular hair. The sensillum lumen is isolated from hemolymph by a cellular barrier. Modified from Steinbrecht (1969) see Steinbrecht (1999) for more details. B Hydrophobic odor molecules enter the aqueous sensillum lumen via pores penetrating the cuticular hair wall. Hydrophilic OBPs are proposed to bind and transport odors to receptor proteins located in the neuronal membranes. ODEs (pathway I) in the sensellum lumen are proposed to degrade these odor molecules. Cytoplasm of support cells contain xenobiotic inactivating enzymes, such as glutathione-S-transferase (GST) (pathway I la) which may also serve to inactivate odor molecules (pathway lib). Interactions between OBPs and ORs and the function of SNMP are unclear. Modified from Rogers et al. (1999).

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