ATP-LINKED EFFECTORS OF NA,K-ATPASE AND CATARACT

晶状体Na+和K+浓度的变化 与增加透镜颜色和增加皮质 不透明 Na，K-ATP酶在37%的上皮细胞中受到抑制， 白内障人群 对透镜Na，K-ATP酶的抑制 皮质更普遍，出现在80- 90%的晶状体中。 拟议研究的目的是表征Na，K- 正常人和白内障上皮和皮质的ATP酶 眼镜. 由于人类白内障晶状体无法用于研究， 将采用动物模型和体外模型系统。 在接下来的五年里，葡萄糖基化的位点， 氨甲酰化和透镜上皮细胞Na，K-ATP酶的氧化 将被定位。 Na ~+、K ~+、Mg ~（2+）、ATP、ADP、Pi、 和哇巴因与三种修饰的Na，K-ATP酶制剂 将被确定。 这将使用稳态 动力学技术、透镜器官培养和透镜上皮细胞 培养技术和非稳态动力学技术 用纯化的肾Na，K-ATP酶在合成膜囊泡中。 将启动研究以表征 表层皮质纤维 皮质中存在的同工酶 将使用针对三种主要 重亚基同工酶测序。 Na，K-ATPase的命运 将确定所选模型白内障的透镜皮质中的白内障。

Changes in lenticular Na+ and K+ concentrations have been correlated with increasing lens color and increasing cortical opacity. Na,K-ATPase is inhibited in epithelium in 37% of the cataract population. Inhibition of the Na,K-ATPase of the lens cortex is more general, occurring in 80-90 percent of the lenses. The purpose of the proposed studies is to characterize the Na,K- ATPase of the epithelium and cortex of normal and cataractous lenses. Since human cataract lenses are not available for study, animal models and in vitro model systems will be employed. During the next five years, the sites of glucosylation, carbamylation, and oxidation of lens epithelial cell Na,K-ATPase will be located. The interaction of Na+,K+,Mg2+,ATP,ADP,Pi, and ouabain with the three modified Na,K-ATPase preparations will be determined. This will be accomplished using steady state kinetics techniques, lens organ culture and lens epithelial cell culture techniques as well as non steady state kinetics techniques with purified renal Na,K-ATPase in synthetic membrane vesicles. Studies will be initiated to characterize the Na,K-ATPase of the superficial cortical fibers. The isozyme(s) present in the cortex will be determined using specific antisera to the three major sequenced heavy subunit isozymes. The fate of the Na,K-ATPase in the lens cortex of selected model cataracts will be determined.