期刊
BIOPHYSICAL JOURNAL
卷 112, 期 2, 页码 288-299出版社
CELL PRESS
DOI: 10.1016/j.bpj.2016.12.008
关键词
-
类别
资金
- Australian Research Council [DP-121003548, DP-150101112]
- Novo Nordisk Foundation
- Lundbeckfonden
- Lundbeck Foundation [R82-2011-7280] Funding Source: researchfish
- Novo Nordisk Fonden [NNF14OC0012437] Funding Source: researchfish
- Villum Fonden [00007292] Funding Source: researchfish
The Na+,K+-ATPase is present in the plasma membrane of all animal cells. It plays a crucial role in maintaining the Na+ and K+ electrochemical potential gradients across the membrane, which are essential in numerous physiological processes, e.g., nerve, muscle, and kidney function. Its cellular activity must, therefore, be under tight metabolic control. Consideration of eosin fluorescence and stopped-flow kinetic data indicates that the enzyme's E2 conformation is stabilized by electrostatic interactions, most likely between the N-terminus of the protein's catalytic alpha-subunit and the adjacent membrane. The electrostatic interactions can be screened by increasing ionic strength, leading to a more evenly balanced equilibrium between the E1 and E2 conformations. This represents an ideal situation for effective regulation of the Na+,K+-ATPase's enzymatic activity, because protein modifications, which perturb this equilibrium in either direction, can then easily lead to activation or inhibition. The effect of ionic strength on the E1 :E2 distribution and the enzyme's kinetics can be mathematically described by the Gouy-Chapman theory of the electrical double layer. Weakening of the electrostatic interactions and a shift toward El causes a significant increase in the rate of phosphorylation of the enzyme by ATP. Electrostatic stabilization of the Na+,K+-ATPase's E2 conformation, thus, could play an important role in regulating the enzyme's physiological catalytic turnover.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据