Name: enzyme action and inhibition
Uploaded: 2020-09-24T15:06:50.000Z
Duration: 2 min 34 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

NC K-12 Science Standard Course of Study

9-12

Chemistry

Matter and its Interactions

PS.Chm.5.1

Enzymes

효소는 생화학 반응 속도를 가속화하는 생물 촉매입니다. 대부분의 효소는 아미노산으로 구성된 단백질이지만 일부 어떤 효소는 리보자임으로 알려진 RNA 분자입니다. 효소는 반응의 활성화 에너지를 낮추어 반응 속도를 증가시키는 작용을 합니다.

효소는 화학 결합의 합성 및 파괴를 촉진시킬 수 있지만 반응의 방향이나 평형에는 영향을 미치지 않습니다. 모든 효소는 기질이라고 불리는 특정한 반응물과 결합하여 특정한 반응을 촉진합니다. 이 기질은 분자간 힘 및 단기 공유 결합과 같은 상호작용을 통해 활성 부위라고 불리는 효소의 별개의 촉매 영역에 결합되어 효소-기질 복합체가 됩니다.

이 결합은 효소와 효소 기질 사이에 필요한 구조적 상호보완성으로 인해 매우 특이합니다. 따라서, 특정 효소는 자체의 적합성에 기초한 특정 반응만을 촉진할 수 있습니다. 복잡한 형성 과정을 이해하는 간단한 방법은 기질이 효소의 활성 부위에 적합하다는 가설을 세운 자물쇠열쇠 모델이며, 이는 해당 자물쇠'에 맞는 열쇠'라고 보면 유사합니다.

그러나 또 다른 모델인 유도 적합 모델에서는 복합물의 동적 특성을 고려합니다. 이 모델은 기질이 결합될 때 작은 적합성 변화를 유도하여 반응을 더 촉진하는 더 밀접한 적합을 형성합니다. 반응을 위한 활성화 에너지는 다양한 방법으로 낮출 수 있습니다.

일반적인 메커니즘에는 결합을 보다 쉽게 파괴할 수 있도록 하는 기질의 적합성 변화를 유도하거나, 두 기질의 반응 집단을 더 근접하게 하여 결합 형성을 촉진하는 것이 포함됩니다. 효소 활동은 억제제라고 불리는 자연 분자나 합성 분자에 의해 일시적으로 또는 영구적으로 억제될 수 있습니다. 예를 들어, 경쟁적 억제제는 기질과 경쟁하여 효소의 활성 부위와 결합하면서 기질 결합을 막습니다.

반면에, 비경쟁 억제제는 효소의 다른 위치와 결합하는데 이를 통해 효소의 촉매적 활성을 감소시키면서 활성 부위에서 구조적인 변화를 일으킵니다.

효소

살아있는 유기체 내부에서 효소는 세포 대사와 관련된 많은 생화학 반응의 촉매제 역할을 합니다. 효소의 역할은 기질과 복합체를 형성하여 생화학 반응의 활성화 에너지를 줄이는 것입니다. 활성화 에너지가 낮아지면 생화학 반응 속도가 빨라집니다.

효소 결핍은 종종 생명을 위협하는 질병으로 이어질 수 있습니다. 예를 들어, G6PD(포도당-6-인산 탈수소효소) 효소의 결핍을 초래하는 유전적 이상은 세포에 NADPH를 공급하는 대사 경로에 부정적인 영향을 미칩니다.

이 대사 경로가 중단되면 적혈구의 글루타티온이 감소하여 헤모글로빈과 같은 다른 효소 및 단백질이 손상될 수 있습니다. 헤모글로빈의 과도한 대사는 빌리루빈 수치를 높여 황달을 유발하며, 황달은 더욱 심각해질 수 있습니다. 따라서 G6PD 결핍으로 고통받는 사람들은 글루타티온 결핍 적혈구에 손상을 유발할 수 있는 화학 물질이 포함된 특정 음식과 의약품을 피해야 합니다.

효소 기능 및 구조

효소는 수행하는 특정 기능에 따라 여러 클래스로 분류됩니다. 예를 들어, 산화환원효소는 산화환원 반응에 관여하는 반면, 전이효소는 작용기의 전달을 촉매합니다. ATP 가수분해에 의한 결합 형성에는 리가아제가 필요한 반면, 가수분해 반응과 이중 결합 형성은 각각 가수분해효소와 리아제에 의해 촉매됩니다. 이성질화효소 효소는 일반적으로 이성질화 반응을 촉매합니다.

효소는 일반적으로 활성 부위를 가지고 있습니다. 이는 효소가 특정 기질(반응물 분자)에 결합하여 효소-기질 복합체 또는 반응 중간체를 형성하는 데 유리한 구조를 가진 분자의 특정 영역입니다.

잠금 및 키 모델과 유도 맞춤 모델이라는 두 가지 모델은 활성 사이트의 작동을 설명하려고 시도합니다(Figure 1). 가장 단순한 자물쇠와 열쇠 가설은 활성 부위와 기질의 분자 모양이 상호보완적이라는 것입니다. 마치 자물쇠의 열쇠처럼 서로 맞춰져 있다는 것입니다(Figure 1a). 반면, 유도 적합 가설은 효소 분자가 유연하고 기질과의 결합을 수용하기 위해 모양이 변한다는 것을 시사합니다(Figure 1b).

그러나 자물쇠-열쇠 모델과 유도적합 모델은 모두 효소가 특정 기질과만 결합할 수 있고 특정 반응만 촉매할 수 있다는 사실을 설명합니다.

<img alt="Eq1" src="/files/ftp_upload/11384/11384_Image_1.png" style="text-align: center; height: 300px;" />

Figure 1 (a) 자물쇠와 열쇠 모델에 따르면 효소의 활성 부위의 모양은 기질에 완벽하게 맞습니다. (b) 유도 적합 모델에 따르면 활성 부위는 다소 유연하며 기판과 결합하기 위해 모양이 바뀔 수 있습니다.

효소 억제제

효소 억제 과정에 의해 효소의 활성이 중단될 수도 있습니다. 효소 억제에는 몇 가지 일반적인 유형이 있습니다.

경쟁적 억제 동안 기질 이외의 분자(천연 또는 합성)가 효소의 활성 부위에 직접 결합합니다. 억제제와 기질의 구조적, 화학적 유사성은 활성 부위에 대한 결합을 촉진합니다. 따라서 이러한 경쟁적 억제제는 기질과 경쟁하여 기질이 효소에 결합하는 것을 방지합니다. 대부분의 경우 기질 농도를 높이면 경쟁 억제 효과를 억제할 수 있습니다.

비경쟁적 억제에서는 분자(천연 또는 합성)가 효소의 활성 부위와 다른 알로스테릭(기타) 영역에 결합합니다. 억제제 결합은 효소 활성 부위의 구조적 변화를 유발하여 반응을 촉매하는 효소의 능력을 감소시킵니다. 경쟁적 억제와 달리 기질 농도의 증가는 비경쟁적 억제의 억제 효과를 완화하지 않습니다.

이 문서는 에서 발췌되었습니다 <a href="https://openstax.org/books/chemistry-2e/pages/12-7-catalysis">Openstax, Chemistry 2e, Section 12.7: Catalysis.</a>

살아있는 유기체 내부에서 효소는 세포 대사와 관련된 많은 생화학 반응의 촉매로 작용합니다. 효소의 역할은 ...

Education

교육

JoVE Core

화학

하나

Chemical Kinetics

화학 반응 속도론

KEY TERMS AND CONCEPTS

주요 용어 및 개념

enzyme action and inhibition

Enzymes are biological catalysts that speed up many reactions in living organisms. They help control cellular metabolism by lowering the activation energy needed for biochemical reactions. When activation energy drops, reaction rates can increase.

Enzyme problems can also lead to serious disease. A genetic abnormality that causes G6PD, or glucose-6-phosphate dehydrogenase, deficiency can disrupt the pathway that supplies NADPH to cells. In red blood cells, this can reduce glutathione and damage other enzymes and proteins such as hemoglobin. As hemoglobin is broken down too much, bilirubin builds up and can cause jaundice. People with G6PD deficiency often need to avoid certain foods and medicines that may trigger damage to their red blood cells.

Enzymes are grouped by the reactions they carry out. Oxidoreductases take part in redox reactions. Transferases move functional groups from one molecule to another. Ligases form bonds and use ATP hydrolysis, while hydrolases drive hydrolysis reactions and lyases help form double bonds. Isomerases catalyze isomerization reactions.

Most enzymes have an active site, which is the region that binds a specific substrate, or reactant molecule. The enzyme and substrate form an enzyme-substrate complex, which acts as the reaction intermediate. Two models explain how this binding works. In the lock-and-key model, the active site and substrate fit together like a key in a lock. In the induced-fit model, the enzyme changes shape to fit the substrate. Both models explain enzyme specificity, meaning an enzyme usually binds only certain substrates and catalyzes only one particular reaction.

Enzyme activity can also be blocked by inhibitors. In competitive inhibition, an inhibitor that is similar to the substrate binds directly to the active site and competes with the substrate. Increasing substrate concentration can often reduce this effect. In non-competitive inhibition, the inhibitor binds to an allosteric site, which is a different region of the enzyme. This binding changes the shape of the active site and lowers enzyme activity. Unlike competitive inhibition, adding more substrate does not fix non-competitive inhibition.

Enzyme Action and Inhibition

reaction rate

Measuring Reaction Rates

Measuring reaction rates shows how fast reactants are used up or products are formed over time. The rate of reaction is the change in the amount of a reactant or product per unit time. Because of that, scientists measure how a property changes as the reaction proceeds and connect that change to reactant or product amounts. For reactions that make or use a gas, the rate can be followed by changes in volume or pressure. A rate expression is the mathematical way to write how concentration changes...

measuring reaction rates

Tracking Reaction Kinetics with Light and Pressure

Reaction kinetics can be tracked with polarimetry, spectrometry, and pressure measurements. These methods let scientists follow a reaction without disturbing the sample. They also help determine how reactant or product concentrations change over time. Polarimetry is used for optically active substances. These substances rotate the plane of polarized light, which is called optical rotation. The effect comes from molecular structure. Normal monochromatic light is unpolarized, but after it passes...

concentration and rate law

Reaction Order from Concentration

Reaction order from concentration shows how reactant amounts affect reaction rate. Rate laws, also called differential rate laws or rate equations, are mathematical expressions that connect reaction rate with the concentrations of reactants. For a generic reaction a A + b B → products, the rate law can be written using the reactant concentrations [A] and [B] and a rate constant k. In a rate law, k is the rate constant for one specific reaction at one specific temperature. The exponents m and n...

determining order of reaction

Finding Rate Law from Initial Rates

Rate laws connect the speed of a chemical reaction to the concentration of its reactants. The rate constant, k, and the reaction orders are not taken from the chemical equation. They are found experimentally by watching how the rate changes when the reactant concentrations change. One common way to do this is the method of initial rates. In this method, several trials are run with different starting concentrations. The measured rates are then compared to determine the reaction orders and,...

the integrated rate law: the dependence of concentration on time

the-integrated-rate-law-the-dependence-of-concentration-on-time

Reading Reaction Progress with Integrated Laws

Integrated rate laws connect reaction concentration to time. They help show how much reactant or product is present after a certain period. They can also help estimate how long a reaction must run to reach a given extent. A common use is finding how long radioactive material must be stored before its radioactivity drops to a safe level. These equations come from the differential rate law after it is integrated with respect to time. For a first-order reaction, where rate = k[A], the integrated...

half-life of a reaction

Reaction Half-Life in Kinetics

Reaction half-life is the time needed for half of a reactant to be consumed. After each half-life, half of the remaining reactant is used up. A hydrogen peroxide decomposition example shows this pattern clearly. The concentration drops from 1.000 M to 0.500 M in the first 6.00 hours, then to 0.250 M in the next 6.00 hours, and then to 0.125 M in the third period. Each later 6.00-hour interval removes half of what is left. For first-order reactions, the half-life does not depend on the reactant...

temperature dependence on reaction rate

Collision Theory and Reaction Speed

Collision theory explains why reaction speed depends on how particles collide. Atoms, molecules, or ions must come close together before they can react. The theory says the reaction rate depends on the collision rate, the orientation of the colliding species, and whether the collision has enough energy for bonds to change. A gas-phase reaction between carbon monoxide and oxygen shows why orientation matters. The molecules can collide in more than one way. If the oxygen side of carbon monoxide...

arrhenius plots

Determining Activation Energy from Temperature

The Arrhenius equation links activation energy and the rate constant, k, for chemical reactions. It is written as k = Ae−Ea/RT. In this equation, R is the ideal gas constant with a value of 8.314 J/mol·K, T is the temperature on the kelvin scale, Ea is the activation energy in J/mole, e is the constant 2.7183, and A is the frequency factor. The frequency factor depends on collision frequency and the orientation of reacting molecules. Experimental kinetic data can be used to find the activation...

reaction mechanisms

Elementary Steps in Reaction Mechanisms

Chemical reactions can happen in steps, and a balanced equation does not show the full path at the molecular level. A reaction mechanism, also called a reaction path, gives the step-by-step process that explains how reactants become products. The decomposition of ozone is one example of a reaction that can be described by a sequence of steps. Each step in a mechanism is an elementary reaction. These elementary reactions happen in order, and when they are added together, they give the balanced...

rate-determining steps

Reaction Bottlenecks in Chemical Kinetics

Reaction bottlenecks help explain rate-determining steps in multistep reaction mechanisms. In a mechanism with several elementary steps, one step is often much slower than the others. That slowest step is called the rate-limiting step, or rate-determining step. A reaction cannot move faster than its slowest step, so this step controls the overall reaction rate. The idea is like traffic on a four-lane freeway with one lane closed. Cars can only move as fast as the bottleneck allows. In the same...

catalysis

Catalyst Action in Reaction Rates

Catalysts change the rate of a chemical reaction by giving it a faster path. A catalyst increases reaction rate without being consumed during the process. Its effect is often explained with reaction mechanisms and energy diagrams. For an endothermic reaction, the reactants and products start and end at the same energies in both cases. The uncatalyzed path is a one-step mechanism with one transition state. The catalyzed path follows a different mechanism with two transition states and a lower...

enzymes

Enzymes are biological catalysts that speed up many reactions in living organisms. They help control cellular metabolism by lowering the activation energy needed for biochemical reactions. When activation energy drops, reaction rates can increase. Enzyme problems can also lead to serious disease. A genetic abnormality that causes G6PD, or glucose-6-phosphate dehydrogenase, deficiency can disrupt the pathway that supplies NADPH to cells. In red blood cells, this can reduce glutathione and...

key terms and concepts

Explore how enzymes speed reactions, how active sites work, and how competitive and non-competitive inhibitors affect enzyme activity in high school biology.

Enzyme Action and Inhibition | JoVE K12

chemistry

JoVE Core 화학은 간결하고 이해하기 쉬운 애니메이션을 통해 일반 화학 개념을 설명합니다. 또한, 과학자가 직접 고전실험과 연구실험을 진행하는 실사 영상을 제공합니다.

Pennsylvania State Academic Standards

Physical Science

Chemical Reactions

3.2.9-12.D

3.2.9-12.E

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Interactions Of Matter

Chemical reactions

Virginia  Standards of Learning

HIgh School

CH.7

CH.7.f

Arizona Science Standards

High School

HS.P1

HS.P1U1.3

Next Generation Science Standards

Matter and Its Interactions

HS-PS1-4

HS-PS1-5

Florida Department of Education

SC.912.P.12

SC.912.P.12.12

Scientific Laws and Theories

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PS.Chm.1.1

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Nuclear Binding Energy

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Radioactive Decay and Radiometric Dating

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Nuclear Fission

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Nuclear Power

Controlled nuclear fission reactions are used to generate electricity. Any nuclear reactor that produces power via the fission of uranium or plutonium by ...

Nuclear Fusion

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Nuclear Transmutation

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Use models to compare nuclear reactions including alpha decay, beta decay and gamma decay; nuclear fusion and nuclear fission.

PS.Chm.1.2

Atomic Orbitals

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The Pauli Exclusion Principle

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The Energies of Atomic Orbitals

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The Aufbau Principle and Hund's Rule

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Electron Configuration of Multielectron Atoms

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PS.Chm.1.3

Periodic Classification of the Elements

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Atomic Mass

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Molar Mass

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PS.Chm.2.1

atomic-radii-and-effective-nuclear-charge

Atomic Radii and Effective Nuclear Charge

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Ionic Radii

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Electron Affinity

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Construct an explanation to infer the atomic size, reactivity, electronegativity, and ionization energy of an element based on its position in the Periodic Table.

PS.Chm.2.2

Types of Chemical Bonds

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Lewis Symbols and the Octet Rule

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Ionic Bonding and Electron Transfer

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The Born-Haber Cycle

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An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure ...

Covalent Bonding and Lewis Structures

Compared to ionic bonds, which results from the transfer of electrons between metallic and nonmetallic atoms, covalent bonds result from the mutual ...

Electronegativity

Whether a bond is nonpolar or polar covalent is determined by a property of the bonding atoms called electronegativity.&#xA0;

Electronegativity values of ...

bond-polarity-dipole-moment-and-percent-ionic-character

Bond Polarity, Dipole Moment, and Percent Ionic Character

Bond Polarity

The absolute value of the difference in electronegativity (&Delta;EN) of two bonded atoms provides a rough measure of the polarity to be ...

lewis-structures-of-molecular-compounds-and-polyatomic-ions

Lewis Structures of Molecular Compounds and Polyatomic Ions

To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:


	Determine the ...

Resonance

The Lewis structure of a nitrite anion (NO2&minus;) may actually be drawn in two different ways, distinguished by the locations of the N-O and N=O ...

Formal Charges

In some cases, there are seemingly more than one valid Lewis structures for molecules and polyatomic ions. The concept of formal charges can be used to ...

Exceptions to the Octet Rule

Many covalent molecules have central atoms that do not have eight electrons in their Lewis structures. These molecules fall into three categories:


	...

Bond Energies and Bond Lengths

Stable molecules exist because covalent bonds hold the atoms together. The strength of a covalent bond is measured by the energy required to break it, ...

Analyze and interpret data to explain the mechanisms and properties of the two main types of intramolecular (ionic and covalent) bonds.

PS.Chm.3.1

molecular-comparison-of-gases-liquids-and-solids

Molecular Comparison of Gases, Liquids, and Solids

Particles in a solid are tightly packed together (fixed shape) and often arranged in a regular pattern; in a liquid, they are close together with no ...

Intermolecular vs Intramolecular Forces

Intermolecular forces (IMF) are electrostatic attractions arising from charge-charge interactions between molecules. The strength of the intermolecular ...

Intermolecular Forces

Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions ...

comparing-intermolecular-forces-melting-point-boiling-point

Comparing Intermolecular Forces: Melting Point, Boiling Point, and Miscibility

Intermolecular forces are attractive forces that exist between molecules. They dictate several bulk properties, such as melting points, boiling points, ...

surface-tension-capillary-action-and-viscosity

Surface Tension, Capillary Action, and Viscosity

Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded ...

Construct an explanation to summarize the influences intermolecular forces have on the properties of chemical compounds.

PS.Chm.3.2

Analyze the structure of atoms and isotopes.

Enzyme Action and Inhibition

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