ISOZYMES OF NA, K-ATPASE--MONOCLONAL ANTIBODY PROBES

已知的心脏糖苷类药物引起的变力作用是由于 抑制Na，K-ATPase。这个实验室发现了 Na，K-ATPase亚型在大脑中的存在，以及它们有 某些强心苷的亲和力明显不同 物种。在第一个支持期，单抗 允许鉴定三种Na，K-ATPase 心脏中的同种异构体。单抗表位为 映射的；用于确定特异性的；用于研究的 跨膜蛋白拓扑学。然后他们被用来评估 大鼠脑内异构体表达的控制因素 心。在发育、甲状腺功能减退和 高血压对于了解心脏的 对药物的生理敏感性。 现在的目标是使用单抗表位映射来 研究Na，K-ATPase异构体的结构。抗体 将有助于对异构体的生化分析。他们会 用来确定细胞内跨膜段的形态 备受争议的C-终端的一半。他们还将被用来 推测哇巴因结合位点的位置。这样的身体 证据补充和检验分子支持的模型 生物学；例如，我们有证据表明哇巴因结合 站点未位于站点定向所指示的位置 诱变。

Cardiac glycoside-elicited inotropy is known to be due to inhibition of the Na,K-ATPase. This laboratory discovered the existence of Na,K-ATPase isoforms in the brain, and that they had markedly different affinities for cardiac glycosides in some species. In the first period of support, monoclonal antibodies were produced that permitted identification of three Na,K-ATPase isoforms in the heart. The monoclonal antibody epitopes were mapped; used to determine specificity; and used to study transmembrane protein topography. They then were used to assess factors that control the expression of the isoforms in the rat heart. Changes were seen during development, hypothyroidism, and hypertension that are important for understanding the heart's physiological sensitivity to the drug. The objective now is to use monoclonal antibody epitope mapping to investigate the structure of the Na,K-ATPase isoforms. Antibodies will aid the biochemical analysis of isoform variants. They will be used to determine the topography of transmembrane segments in the controversial C-terminal half. They will also be used to deduce the location of the ouabain binding site. Such physical evidence complements and tests models supported by molecular biology; for example, we have evidence that the ouabain binding site is not located at the position indicated by site-directed mutagenesis.