What is the Difference Between Non-Competitive and Allosteric Inhibition

Thekey difference在非竞争和变构抑制之间is that in non-competitive inhibition, the maximum rate of catalyzed reaction (Vmax) decreases and substrate concentration (Km) remains unchanged, while in allosteric inhibition, Vmax remains unchanged and Km increases.

酶对于在生物体中发生的大多数反应至关重要。通常，酶通过减少反应所需的激活能来催化反应。但是，应仔细调节酶，以控制最终产品的水平上升到不希望的水平。它受酶抑制的控制。酶抑制剂是打扰酶和底物之间正常反应途径的分子。

一个active site is the region of an enzyme where the基材结合并经历化学反应。变构位置是允许分子激活或抑制酶活性的地方。酶动力学在酶抑制过程中起重要作用。在特定浓度下特定酶的最大反应特征称为最大速度或VMAX。给出VMAX一半的速率的底物浓度为km。

内容

1.Overview and Key Difference
2.What is Non-Competitive Inhibition
3.What is Allosteric Inhibition
4.Similarities – Non-Competitive and Allosteric Inhibition
5.非竞争力与变构抑制in Tabular Form
6.Summary – Non-Competitive vs Allosteric Inhibition

What is Non-Competitive Inhibition?

Non-competitive inhibition is a type of enzyme inhibition where the inhibitor reduces the enzyme activity and binds equally well to the enzyme, whether it is bound to the substrate or not. In other words, non-competitive inhibition is where the inhibitor and substrate both bind to the enzyme at any given time. When both substrate and inhibitor bind with the enzyme, it forms an enzyme-substrate-inhibitor complex. Once this complex is formed, it cannot produce any product. It can only convert back to the enzyme-substrate complex or the enzyme-inhibitor complex.

在非竞争激烈的抑制作用中，抑制剂对酶和酶 - 基底络合物具有相等的亲和力。非竞争性抑制剂的最常见机制是抑制剂与变构位点的可逆结合。但是抑制剂还具有直接与活性位点结合的能力。非竞争性抑制剂的一个例子是将丙酮酸激酶转化为丙酮酸。磷酸烯醇丙酮酸转化以产生丙酮酸的转化是通过丙酮酸激酶催化的。一个氨基酸称为从丙酮酸合成的丙氨酸，在糖酵解过程中抑制丙酮酸酶激酶。丙氨酸充当非竞争性抑制剂。

What is Allosteric Inhibition?

变构抑制is a type of enzyme inhibition where the inhibitor slows down the enzyme activity by deactivating the enzyme and binding to the enzyme at the allosteric site. Here, the inhibitor does not directly compete with the substrate at the active site. But, it indirectly changes the composition of the enzyme. Once the shape is changed, the enzyme becomes inactive. Thus, it can no longer bind with the corresponding substrate. This, in turn, slows down the formation of final products.

变构抑制prevents the formation of unnecessary products, reducing energy wastage. An example of allosteric inhibition is the conversion ofADP to ATPin glycolysis. Here, when there is excess ATP in the system, ATP serves as an allosteric inhibitor. It binds to phosphofructokinase, which is one of the enzymes involved in glycolysis. This slows down the ADP conversion. As a result, ATP prevents the unnecessary production of itself. Therefore, excess production of ATP is not needed when there are adequate amounts.

What are the Similarities Between Non-Competitive and Allosteric Inhibition?

• Both types of enzyme inhibitions slow down enzyme activity.
• The inhibitors in both enzyme inhibitions do not compete with the substrate at the active site.
• The inhibitors change the composition of the enzyme indirectly.
• Both inhibitors change the shape of the enzyme.

非竞争性和变构抑制有什么区别？

In non–competitive inhibition, the Vmax of the reaction decreases while leaving the Km value unchanged. In contrast, in allosteric inhibition, the Vmax remains unchanged, and the Km value increases. So, this is the key difference between non–competitive and allosteric inhibition. Allosteric inhibition focuses more on the usage of chemicals which alters the enzyme activity by binding at an allosteric site, while non-competitive inhibitors always stop the working enzyme by directly binding at an alternative site.

以下信息图表了并排比较的非竞争力和变构抑制之间的差异。

Summary – Non-Competitive vs Allosteric Inhibition

非竞争性抑制是一种酶抑制作用，其中抑制剂降低酶活性并与酶同样结合，无论它是否与底物结合。变构抑制是一种酶抑制作用，其中抑制剂通过失活酶并在变构位点与酶结合而减慢了酶活性。非竞争和变构抑制之间的关键差异是，催化反应的最大速率（VMAX）降低，底物浓度（km）在非竞争激烈抑制中保持不变，而VMAX保持不变，并且在相骨中增加了KM，则增加抑制。

Reference:

1.“”变构法规：协议。”乔夫。
2. “Enzymes。”无限的微生物学。

Image Courtesy:

1.“”Competitive&NonCompetitive Enzyme Inhibition” By California16 – Own work(CC BY-SA 4.0)via Commons Wikimedia
2. “变构抑制” by [[：en：user：{{{1}}}} | {{{{1}}}}]]在英语wikipedia上(CC BY-SA 3.0)via Commons Wikimedia