Name: competitive vs noncompetitive inhibitors
Uploaded: 2025-10-23T11:48:34.000Z
Duration: 1 min 30 s
Channel: JoVE

특정 화학 물질은 효소 활동을 억제, 차단 함으로서 기능을 통제 할 수 있습니다.특정 화학 물질은 효소 활동을 억제, 차단 함으로서 기능을 통제 할 수 있습니다.효소 억제제는 두 개의 유형으로 나타나며경쟁적, 비경쟁적이 유형이 있습니다.경쟁적 억제제는효소의 특정 기질과 비슷합니다.비슷한 점은 활성 부위에 결합하고, 기질이 결합하는 것으로부터 차단 할 수 있다는 부분입니다.비슷한 점은 활성 부위에 결합하고, 기질이 결합하는 것으로부터 차단 할 수 있다는 부분입니다.이 활동은 근본적으로 기질로 결합할 수 있는 효소들의 개수를 낮춥니다.이 활동은 근본적으로 기질로 결합할 수 있는 효소들의 개수를 낮춥니다.그에 반해서, 비경쟁적 억제제는아직 영향을 주지만 활성 부위로부터 떠나서 결합하며이는 효소의 모양을 바꿈으로써 이루어집니다.예를들어, 기질이 활성 부위에 결합하지 못하게 친화력을 크게 낮춰예를들어, 기질이 활성 부위에 결합하지 못하게 친화력을 크게 낮춰효소가 제대로 기능하지 못하게 막습니다.게다가, 두 개의 억제제 모두화학 반응 속도에 각각 다른 영향을 미칩니다.대조 구인 보통의 효소 반응 비율에 비교하면경쟁적 억제제를 포함한 반응은최대의 반응 속도인 최고 속도에 닿으려면 더 오랜 시간이 걸리고더 많은 기질도 필요하기 때문입니다.이는 활성 부위에 접근하기 위해 억제제를 계속 뛰어넘는이는 활성 부위에 접근하기 위해 억제제를 계속 뛰어넘는충분한 기질이 있어야 하기 때문입니다.반면에, 비경쟁적 억제제는최고 속도에 미치지 않도록 합니다.왜냐하면, 결합이 가능한 효소의 개수가 줄어들었기 때문입니다.왜냐하면, 결합이 가능한 효소의 개수가 줄어들었기 때문입니다.

Goh, Ee Teng, Marsha Y. Morgan. "알코올 의존에 대한 약물 요법 – 왜, 무엇을, 왜, 그리고 왜." Alimentary Pharmacology & Therapeutics 45, no. 7 (2017): 865-882. [<a href="https://doi.org/10.1111/apt.13965">출처</a>]

효소 억제

Enzyme Inhibition

억제제(inhibitor; 저해제)는 효소와 결합해 효소의 활동을 감소시키는 분자입니다. 정상적으로 작동하는 세포에서 효소는 다양한 억제제에 의해 조절됩니다. 약물과 다른 독소들도 효소를 억제할 수 있습니다. 어떤 억제제들은 효소의 활성부위(active site)와 결합하는 반면, 다른 억제제들은 단백질 구조의 다른 부위와 결합함으로써 효소 활동을 억제합니다.
 
 경쟁적 억제제(competitive inhibitor)는 효소의 활성부위를 차지하여 기질(substrate)을 수용할 수 없게 만듭니다. 그러나 매우 높은 농도의 기질은 억제제를 능가할 수 있습니다. 이에 따라 경쟁적 억제제는 효소의 초기 반응 속도를 늦추지만, 효소의 최대 반응 속도에 영향을 미치지 않습니다. 경쟁적 억제제의 한 예는 만성 알코올 중독을 치료하기 위해 사용되는 약물 디설피람(disulfiram)입니다. 알코올이 섭취될 때, 알코올은 보통 아세트알데히드(acetaldehyde)로 변환되고, 아세트알데히드탈수소효소(acetaldehyde dehydrogenase)에 의해 아세틸조효소A(acetyl coenzyme A, 줄여서 acetyl CoA; 아세틸 CoA)로 변환됩니다. 디설피람은 아세트알데히드탈수소효소의 활성부위와 결합해 자리를 점유하여 효소가 이러한 변환을 수행할 수 없게 합니다. 그 결과, 디설피람을 복용하는 환자는 즉시 두통 등 숙취와 같은 증상을 경험하기 시작하여 알코올 섭취를 감소시킵니다.
 
 비경쟁적 억제제는 활성부위에서 멀리 떨어진 효소의 개별 부위와 결합합니다. 해당 부위를 다른자리입체성 부위(allosteric site)라고 부르며, 분자들이 그 부위에 결합하면, 효소가 기질에 더 낮은 친화력을 갖도록 활성부위의 모양이 바뀝니다. 비경쟁적 억제제가 활성부위를 차지하지 않기 때문에, 추가 기질의 존재는 비경쟁 억제를 극복할 수 없고 효소는 최대 반응 속도를 달성할 수 없습니다.
 
 억제제와 효소 사이의 공유결합(covalent bond)은 보통 일부 독소의 경우처럼 되돌릴 수 없습니다. 세포에서 일반적으로 활동하는 대부분의 조절 억제제는 약한 상호작용을 통해 효소와 상호작용합니다. 이러한 유형의 결합은 가역적(reversible)이며 물질대사 과정의 조절에 유용합니다. 암의 세포 성장을 조절하는 효소를 경쟁적 또는 비경쟁적으로 억제하기 위한 새로운 분자를 찾기 위해 연구가 활발히 진행되고 있습니다.

억제제는 효소에 결합하여 효소 활성을 감소시키는 분자입니다. 정상적으로 기능하는 세포에서 효소는 다양한 ...

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competitive vs noncompetitive inhibitors

Enzyme inhibitors are molecules that reduce enzyme activity by binding to enzymes. Cells use these inhibitors to help regulate normal enzyme function. Drugs and toxins can also block enzymes and change how they work.

Some inhibitors bind at the active site, which is the part of the enzyme where the substrate normally fits. Competitive inhibitors do this by occupying the active site and preventing the substrate from binding. If the substrate concentration becomes high enough, it can outcompete the inhibitor. For that reason, competitive inhibitors slow the initial reaction rate but do not change the enzyme’s maximum rate.

A clear example is disulfiram, a drug used to treat chronic alcoholism. Alcohol is normally converted to acetaldehyde and then to acetyl coenzyme A by acetaldehyde dehydrogenase. Disulfiram binds to the active site of acetaldehyde dehydrogenase and blocks this conversion. This causes hangover-like symptoms, such as headache, and helps decrease alcohol consumption.

Noncompetitive inhibitors bind at a different part of the enzyme. These binding sites are called allosteric sites. When a noncompetitive inhibitor binds, it changes the shape of the active site and lowers the enzyme’s affinity for the substrate. Extra substrate cannot overcome this effect, so the enzyme cannot reach its maximum reaction rate.

Some inhibitors form covalent bonds with enzymes. This binding is usually irreversible, as with some toxins. Most inhibitors that regulate metabolism in cells bind more weakly. That weak binding is reversible and helps control metabolic processes. Researchers also study enzyme inhibitors as possible treatments for cancers that involve cell growth.

Competitive vs Noncompetitive Inhibitors

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Metabolism is the set of chemical reactions that happen in a cell. It includes anabolism, which builds molecules, and catabolism, which breaks them down. These reactions help cells manage energy and keep life processes running. Cells use metabolism to turn food into energy, make cell parts, and remove waste products. Food stores potential energy in the bonds between atoms. Catabolic pathways break large food molecules into smaller ones and release that energy. Anabolic pathways use that energy...

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potential energy

Stored Energy in Motion and Bonds

Stored energy in motion and bonds is called potential energy. It depends on the structure of an object or the position of matter in space. Raising a kettlebell changes its location and increases its potential energy. A stretched rubber band also stores potential energy, which can later change into kinetic energy. Chemical bonds between atoms hold another form of stored energy called chemical energy. These bonds involve attractive forces, and that energy can change into other forms during a...

free energy

Gibbs Free Energy in Chemical Reactions

Gibbs free energy is a measure of useful energy that can be taken from a chemical reaction to do work. It is written as G and named for scientist Gibbs, who discovered it. This energy is what remains after entropy is considered. A reaction can either take in energy or release it. Reactions that absorb energy are called endergonic reactions. Reactions that release energy are called exergonic reactions. The direction of energy flow helps show which type of reaction is happening. Plants carry...

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phosphorylation

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enzyme kinetics

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enzyme inhibition

Enzyme inhibitors are molecules that reduce enzyme activity by binding to enzymes. Cells use these inhibitors to help regulate normal enzyme function. Drugs and toxins can also block enzymes and change how they work. Some inhibitors bind at the active site, which is the part of the enzyme where the substrate normally fits. Competitive inhibitors do this by occupying the active site and preventing the substrate from binding. If the substrate concentration becomes high enough, it can outcompete...

feedback inhibition

How Cells Control Product Buildup

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allosteric regulation

Allosteric Control of Enzyme Speed

Allosteric control changes enzyme speed when a molecule binds to a site other than the active site. That alternate binding spot is called an allosteric site. An enzyme can have more than one allosteric site. This type of control can raise or lower enzyme activity. Many enzymes with allosteric control are metabolic enzymes. They help with the breakdown or the building of specific molecules in cells. In allosteric inhibition, the effector molecule causes a shape change that lowers the enzyme's...

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key terms and concepts

Compare competitive and noncompetitive enzyme inhibitors, including active-site binding, allosteric effects, disulfiram, and how inhibitors regulate cells.

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Competitive vs Noncompetitive Inhibitors

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