跨膜和外周蛋白之间的差异

关键区别 - 跨膜vs Peripheral Proteins

这fluid mosaic model that was discovered in 1972 by Singer and Nicolson explains the structure of universal细胞膜围绕细胞及其organelles。It has been evolved over the years, and it explains the basic structure and function of the cell membrane. The质膜is the model which protects the cells from damages, and it provides protection against foreign agents. According to fluid mosaic model, the plasma membrane is made up of bilayered lipids sheets (phospholipids),cholesterol,carbohydrates, andproteins。发现胆固醇附着在脂质双层。碳水化合物要么附着在膜中的脂质或蛋白质上。这membrane proteins are of three types:integral proteins，外周蛋白和跨膜蛋白。整合蛋白被整合到膜中。这key difference在跨膜蛋白和外周蛋白之间，transmembrane proteins extend all the way across the membrane while the peripheral proteins are attached loosely to the inside and outside surfaces.

内容

1.Overview and Key Difference
2.什么是跨膜蛋白
3.What is a Peripheral Protein
4.Similarities Between Transmembrane and Peripheral Proteins
5.Side by Side Comparison – Transmembrane vs Peripheral Proteins in Tabular Form
6。概括

什么是跨膜蛋白？

跨膜蛋白是贯穿生物细胞膜的特殊类型的整合蛋白。它是永久连接的，可以完全跨越整个膜。大多数跨膜蛋白都作为网关工作，允许将其他物质运输到内部细胞。跨膜蛋白具有疏水线圈和螺旋，可稳定其在脂质双层中的位置。跨膜蛋白的结构分为三个结构域。脂质双层中的域称为脂质双层域。在外部细胞中发现的结构域称为细胞外域。内部的域被称为细胞内结构域。

Though the plasma membrane is fluidic, the orientations of the transmembrane proteins do not change. These proteins are so large and have high molecular weight. So the rate of changing orientation is very small. The extracellular part is always outside the cell, and intracellular part is always inside the cell.

跨膜蛋白在细胞中发挥了几种非常重要的功能。他们在细胞通信中起关键作用。他们向内部单元格发出有关外部环境的信息。受体可以连接到细胞外域中的物质上。一旦蛋白质与底物结合，它就会为蛋白质的细胞内结构域带来几何变化。这些变化带来了产生级联反应的细胞中蛋白质的几何形状的几种变化。跨膜蛋白能够充当内部细胞的信号传感器。他们发起了对外部环境响应的信号，并导致细胞其他部分发生的动作。

跨膜蛋白还能够控制整个细胞膜的材料和物质的交换。它们可以形成可以通过细胞膜的专门通道或称为“孔蛋白”的通道。这些孔蛋白受到其他有时会封闭甚至有时打开的蛋白质调节。最好的例子是神经细胞信号转导。受体蛋白与A结合neurotransmitter。这个绑定允许打开离子通道(卷tage-gated or ligand-gated channels). And it makes the flow of ions across the channels. Hence, it transmits nerve impulses. The nerve cells transmit electrical signals known as an action potential by the flow of ions across the cell membrane.

What is a Peripheral Protein?

这些蛋白质在时间上附着在质膜上。它们要么连接到整体膜蛋白或脂质双层。外围蛋白通过通过细胞膜结合氢键。这y have several important biological functions. Most of them are working as cell receptors. Some of them are very important enzymes. As they are in the cytoskeleton, they give shape and support. They facilitate movement through three main components:microfilaments，中间细丝，microtubules。这ir main function is transportation. They carry molecules between other proteins. The best example is “Cytochrome C,” which carries electron molecules between proteins in the electron transport chain of energy generation.

So, peripheral proteins are extremely important for cell survival. When the cell damages, “Cytochrome C” is released from the cell. This is led to the凋亡of the cell. Some of the peripheral enzymes participate in the metabolism are; lipoxygenase, alpha-beta hydrolase, phospholipase A and C, sphingomyelinase C and Ferrochelatase.

What are the Similarities Between Transmembrane and Peripheral Proteins?

• 两者都是蛋白质。
• 两者都参与分子运输。
• Both are found in the plasma membrane.
• 两者对于细胞存活非常重要。

What is the Difference Between Transmembrane and Peripheral Proteins?

Transmembrane vs Peripheral Proteins
跨膜蛋白是膜蛋白，一直延伸到整个膜。	外围蛋白是膜蛋白，它们在内部和外表面松散附着。
功能
Transmembrane proteins help in cell signaling.	Peripheral proteins maintain cell shape and support cell membrane to maintain its structure.
Nature
Transmembrane proteins are a type of integral proteins.	外围蛋白不是整合蛋白。
地点
跨膜蛋白在整个细胞膜上延伸。	Peripheral proteins are attached to the surface outside or inside the cell membrane.
Binding
跨膜蛋白永久连接到细胞膜（固定）。	Peripheral proteins are attached temporally or loosely to the cell membrane (orientation is changing).

概括– Transmembranevs Peripheral Proteins

质膜是保护细胞免受损害的模型，并为外国代理提供了保护。质膜的液体镶嵌模型解释了它由脂质双层，胆固醇，碳水化合物和蛋白质组成。发现胆固醇附着在脂质双层。碳水化合物要么附着在膜中的脂质或蛋白质上。蛋白质是三种类型：积分，周围和跨膜蛋白。整合蛋白被整合到膜中，并一直延伸到整个膜。周围蛋白质和外围蛋白均匀连接到内部和外表面。这是跨膜和外周蛋白之间的差异。

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Reference:

1.“跨膜蛋白”。化学解释了。Available here
2.“周围膜蛋白。”Wikipedia，Wikimedia基金会，2017年11月11日。Available here

Image Courtesy:

1.'transmmbrane蛋白的Meng-Jou Wu在英语Wikibooks上 - 使用CommonShelper从En.Wikibooks转移到Adrignola。（公共领域）通过Commons Wikimedia
2.’Membrane protein’By Meng-jou wu at English Wikibooks – Transferred from en.wikibooks to Commons by Adrignola using CommonsHelper. (Public Domain) viaCommons Wikimedia