相关实验视频

Updated: Jun 6, 2025

Measuring Cation Transport by Na,K- and H,K-ATPase in Xenopus Oocytes by Atomic Absorption Spectrophotometry: An Alternative to Radioisotope Assays

Measuring Cation Transport by Na,K- and H,K-ATPase in Xenopus Oocytes by Atomic Absorption Spectrophotometry: An Alternative to Radioisotope Assays

Published on: February 19, 2013

Na⁺转位在H⁺上占主导地位 - - 转位在具有双重运输特异性的膜铁酸酶中

Alexander V Bogachev¹, Viktor A Anashkin¹, Yulia V Bertsova¹

¹Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119899, Russia.

International journal of molecular sciences

|November 27, 2024

概括

阴离子送膜铁酸盐酶 (mPPases) 运输离子. 这项研究显示,Na+,H+-PPase为每一个H+运输8个Na+离子,这表明Na+向的输送有限.

科学领域:

生物化学生物化学
分子生物学分子生物学
膜运输运输膜运输

背景情况:

阴离子膜酸盐酶 (mPPases) 是关键的膜蛋白,参与细胞膜的离子运输.
这些酶表现出不同的运输特异性,从强制性质子 (H+) 载体到/质子 (Na+/H+) 联合载体.
现有的模型表明,H+运输的直接合机制和Na+运输的"十亿"机制,但这些并不能完全解释同时运输的Na+/H+.

研究的目的:

为了研究来自*Bacteroides vulgatus*的Na+,H⁺共载体的运输固体测量和机制.
探索 (Na+) 和质子 (H+) 运输反应之间的关系,由这种酶催化.
阐明在 Na⁺,H⁺-PP 阶段同时发生的阳离子传输的基本机制.

主要方法:

使用基于pyranine的光试验来监测跨膜囊泡的阳离子转位.
采用停止流程技术进行实时运动测量.
操纵实验条件,包括使用H+离子体,以选择性地测量Na+或H+流量.

主要成果:

证明 *Bacteroides vulgatus* Na⁺,H⁺-PPase 运输 Na⁺ 和 H⁺ 在约1.8的固定比率中.
观察到,这种运输比率是独立于外部Na度的.
这些发现支持了"扩展的比利时"模型,表明Na+向酶加载部位的递送有动力限制.

结论:

纳+,H+-PP酶表现出一种独特的运输固体几何学,对Na+比H+更喜欢.
"扩展的比利时"模型为理解观察到的运输机制提供了一个框架.
动力因素,特别是Na+传递的速度,似乎是整体运输过程中的速度限制因素.

关键词:

157个ETH 157个ETH 157个ETH 纳米+ 是用来的.十亿游戏机制的机制直接合直接合能源合器的能源合器质子是一个质子.皮拉宁 (Pyranine) 是一种氨酸.停止了流动,停止了流动.运输检测测量测量测量测量

更多相关视频

Application of Electrophysiology Measurement to Study the Activity of Electro-Neutral Transporters

Application of Electrophysiology Measurement to Study the Activity of Electro-Neutral Transporters

Published on: February 3, 2018

Screening for Thermotoga maritima Membrane-Bound Pyrophosphatase Inhibitors

Screening for Thermotoga maritima Membrane-Bound Pyrophosphatase Inhibitors

Published on: November 23, 2019

相关概念视频

Primary Active Transport

Primary Active Transport

In contrast to passive transport, active transport involves a substance being moved through membranes in a direction against its concentration or electrochemical gradient. There are two types of active transport: primary active transport and secondary active transport. Primary active transport utilizes chemical energy from ATP to drive protein pumps embedded in the cell membrane. With energy from ATP, the pumps transport ions against their electrochemical gradients—a direction they would...

Active Transport

Active Transport

Active transport is a critical biological process that allows cells to move solutes against an electrochemical gradient. This process requires direct energy input and is characterized by its selectivity, saturability, and susceptibility to competitive inhibition.
Primary active transporters, like Na+, K+ and -ATPase, directly utilize ATP to move ions across the membrane. These transporters play significant roles in various physiological processes. For instance, Na+, K+ and -ATPase maintain...

Energy to Drive Translocation

Energy to Drive Translocation

Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...

ATP Driven Pumps I: An Overview

ATP Driven Pumps I: An Overview

ATP-driven pumps, also known as transport ATPases, are integral membrane proteins. They have binding sites for ATP located on the membrane's cytosolic side and the ion-conducting domain in the transmembrane region. These pumps use the free energy released from ATP hydrolysis to move the solutes across cell membranes against an electrochemical gradient.
There are four main types of ATP-driven pumps - P-type, V-type, F-type, and ABC transporter. All these pumps are of varying complexities and...

ATP Driven Pumps II: P-type Pumps

ATP Driven Pumps II: P-type Pumps

The P-type pumps are a large family of integral membrane transporter ATPases. They are divided into five major types based on substrate specificity, from I to V.
A typical P-type pump has three cytosolic domains: nucleotide-binding (N), phosphorylation (P), and activator (A) domains. These domains are connected to the membrane-spanning helices by short amino acid segments. ATP hydrolysis and covalent phosphoenzyme intermediate formation are crucial parts of the catalytic cycle. At the highly...

Secondary Active Transport

Secondary Active Transport

One example of how cells use the energy contained in electrochemical gradients is demonstrated by glucose transport into cells. The ion vital to this process is sodium (Na+), which is typically present in higher concentrations extracellularly than in the cytosol. Such a concentration difference is due, in part, to the action of an enzyme “pump” embedded in the cellular membrane that actively expels Na+ from a cell. Importantly, as this pump contributes to the high concentration of...