Receptor Proteins in Vertebrate Olfaction

普莱斯博士研究的长期目标是了解空气中的化学物质刺激鼻子中的嗅觉感受器细胞从而导致气味感知的机制。推测的一种机制是，气味化学物质(气味物质)与细胞表面的特定受体蛋白结合，导致细胞产生神经冲动。这项研究项目将检验从含有嗅觉感受器细胞的组织中分离出来的某些蛋白质实际上是受体蛋白质的假设，并将对蛋白质特性进行确定。通过亲和层析分离蛋白质利用了它们能结合某些气味这一事实。气味类似物被连接到固体载体上，并制成柱子，组织提取物通过柱子通过。结合气味的蛋白质通常也会结合类似物。类似物连接到固体载体上，因此这些蛋白质与提取物中的数千种其他化学物质分离。通过用类似物的浓缩溶液洗涤固体载体-类似物-蛋白质复合体来回收蛋白质。结合一种气味并不能证明蛋白质是一种受体。这个问题是通过制备与蛋白质不同部分相互作用的抗体(所谓的单抗)来解决的。这些抗体被应用于嗅觉感受器组织，并测量对气味的反应。如果蛋白质是一种受体，一些抗体应该会阻止它与气味结合，从而抑制反应。已经从嗅觉组织中分离出两种蛋白质，并进行了这项测试。结果表明，它们是受体。假设受体蛋白由一系列相似的蛋白质组成。一些针对上述两种蛋白质的抗体抑制了对几种无关气味的反应。这一发现与所提出的假设是一致的；抗体可能与所有受体蛋白共有的部分蛋白质相互作用。这两种蛋白质通过电泳法无法区分，电泳法根据蛋白质在电场中移动的速度来估计蛋白质的大小。这也与受体蛋白构成一个结构类别的假设一致。这些研究旨在通过寻找和比较更多的蛋白质来详细说明上述研究。样本将被提供给其他研究人员，用于他们对嗅觉机制的实验。

The long term objective of Dr. Price's research is to understand the mechanism (or mechanisms) by which chemicals in the air stimulate olfactory receptor cells in the nose, thus leading to odor perception. One mechanism suggested is that the odorous chemicals (odorants) bind to specific receptor proteins on the surface of the cells, which causes the cells to generate nerve impulses. This research project will test the hypothesis that certain proteins isolated from the tissue containing olfactory receptor cells are, in fact, receptor proteins and a determination of the protein characteristics will be made. Isolating the proteins by affinity chromatography takes advantage of the fact that they bind certain odorants. Odorant analogues are linked to solid supports and made into columns through which tissue extracts are passed. Proteins that bind odorants often bind the analogues as well. The analogues are linked to the solid support, thus these proteins are separated from the thousands of other chemicals in the extracts. The proteins are recovered by washing the solid support-analogue-protein complex with concentrated solutions of the analogue. Binding an odorant does not prove that a protein is a receptor. This problem is approached by preparing antibodies that interact with different parts of the protein (so-called monoclonal antibodies). The antibodies are applied to olfactory receptor tissue and responses to odorants are measured. If the protein is a receptor, some of the antibodies should prevent it from binding the odorant and, therefore, inhibit responses. Two proteins have been isolated from olfactory tissue and subjected to this test. The results suggest that they are receptors. Receptor proteins are hypothesized to comprise a family of similar proteins. Some antibodies against each of the two proteins mentioned inhibit responses to several unrelated odorants. This finding is consistent with the stated hypothesis; the antibodies probably interact with part of the protein that is common to all receptor proteins. The two proteins are indistinguishable by electrophoresis, which estimates protein size on the basis of the rate at which it moves in an electric field. This, too, is consistent with the hypothesis that receptor proteins comprise a structural class. These studies are intended to elaborate upon the investigations described above by seeking and comparing additional proteins. Samples will be provided to other investigators for use in their experiments on olfactory mechanisms.