Sklar P B, Anholt R R, Snyder S H
J Biol Chem. 1986 Nov 25;261(33):15538-43.
We have characterized odorant-stimulated adenylate cyclase activity in isolated chemosensory cilia prepared from frog and rat olfactory epithelium. Cilia from both species exhibit high levels of adenylate cyclase activity. Basal activity is stimulated approximately 2-fold by GTP and approximately 5-fold by guanosine 5'-(3-O-thio)triphosphate and forskolin. Odorants augment enzyme activity 30-65% above the basal level in a tissue-specific and GTP-dependent manner. Calcium reduces GTP-stimulated activity with a 50% effective concentration at 10 microM. Odorants vary in their influence upon olfactory adenylate cyclase activity. Most fruity, floral, minty, and herbaceous odorants stimulate the enzyme. 3,7-Dimethyl-2,6-octadienenitrile (citralva), menthone, D-carvone, L-carvone, and 2-isobutyl-3-methoxypyrazine display similar potencies in activating the adenylate cyclase upto concentrations of 100 microM. Putrid odorants, such as isovaleric acid, triethylamine, pyridine, thiazole, and methoxypyrazine, and odorous chemical solvents, do not stimulate enzyme activity. In homologous series of pyrazine, thiazole, and pyridine odorants, compounds with the longest hydrocarbon side chains are best able to enhance enzyme activity. The failure of certain odorants to affect adenylate cyclase activity suggests that additional transduction mechanisms besides the formation of cAMP are involved in olfaction.
我们已对从青蛙和大鼠嗅觉上皮制备的分离化学感受纤毛中的气味刺激腺苷酸环化酶活性进行了表征。这两个物种的纤毛均表现出高水平的腺苷酸环化酶活性。基础活性被GTP刺激约2倍，被鸟苷5'-(3-O-硫代)三磷酸和福司可林刺激约5倍。气味剂以组织特异性和GTP依赖性方式使酶活性比基础水平提高30 - 65%。钙以10微摩尔的50%有效浓度降低GTP刺激的活性。不同气味剂对嗅觉腺苷酸环化酶活性的影响各不相同。大多数果味、花香、薄荷味和草本气味剂刺激该酶。3,7 - 二甲基 - 2,6 - 辛二烯腈（柠檬醛）、薄荷酮、D - 香芹酮、L - 香芹酮和2 - 异丁基 - 3 - 甲氧基吡嗪在浓度高达100微摩尔时激活腺苷酸环化酶的效力相似。腐臭气味剂，如异戊酸、三乙胺、吡啶、噻唑和甲氧基吡嗪，以及有气味的化学溶剂，不刺激酶活性。在吡嗪、噻唑和吡啶气味剂的同系物系列中，具有最长烃侧链的化合物最能增强酶活性。某些气味剂未能影响腺苷酸环化酶活性表明，除了cAMP的形成之外，嗅觉还涉及其他转导机制。
