Mechanism of Enzyme Action | Importance of Enzymes in Biological Processes
Do you know our body also runs on chemistry? The core of this process lies in the mechanism of enzyme action. Enzymes are tiny yet powerful molecules, also known as biological catalysts, that enable biochemical reactions to take place faster and efficiently inside living cells.
The mechanism of enzyme action interprets how enzymes help to speed up the reactions by lowering the activation energy of a reaction. The unique enzyme structure is responsible for its unique functions, allowing it to participate in vital biological processes under mild conditions of temperature and pH. Their efficiency is due to their structure, which allows them to recognize and bind specific molecules with high accuracy.
They follow principles of chemical kinetics and catalysis to ensure that Numerous biological functions inside the body occur in a controlled manner within time. So, we can conclude that the enzyme plays an important role in biological processes. In this article, we will discuss the importance of enzymes in biological processes, enzyme action, and enzyme structure.
The Chemical Nature of Enzymes
The chemical nature of the enzyme is closely related to the mechanism of action of the enzyme . Mostly, enzymes are globular proteins that have a crucial role in enzyme action during many biological processes. They have a 3-dimensional enzyme structure, which allows them to recognize and bind with the substrates specifically. In many cases, enzymes require a cofactor, mostly a metal ion or organic molecule, for the enzyme actions to be completed. This cofactor is also called a coenzyme, which assists enzymes in carrying out the catalytic reactions efficiently.
Enzyme-substrate complex and active sites
Enzyme actions involve the binding of the substrate to the active sites of the enzyme. The active site is a specific region in the enzyme where the substrate binds specifically, and these are formed due to the folding of the protein molecule in the enzyme structure, forming a 3-D enzyme structure. The binding of the substrate to the active site of the enzyme occurs through weak intermolecular forces such as hydrogen bonds, ionic interactions, and Van der Waals forces. That is why they form a temporary ES complex called the Enzyme-Substrate complex during enzyme action. This complex will form and exist only for a short time, and once the product is formed, the complex will break down, in which the substrate detaches from the enzyme, leaving it unchanged. The high specificity of this interaction is a vital part of the mechanism of enzyme action because it highlights the importance of enzymes in regulating many biological processes efficiently.
Enzyme Action Theories
- Lock and Key Model:
In this model, the active sites of the enzymes are rigid and have a fixed shape. They will fit precisely into the active sites to form an enzyme-substrate complex. This is similar to how a key would fit into a lock.
- Induced Fit Model:
In this model, the active site of the enzyme is not fixed but flexible. When a substrate binds to the active site, the enzyme undergoes conformational changes so that the substrate fits perfectly into it to form an E-S complex. Such a type of change will enhance the interaction between the enzyme and substrate and increase catalytic efficiency
Mechanism of Enzyme Catalysis
Enzymes help in speeding up the chemical reactions by lowering the activation energy, which is required for a reaction to begin. They stabilize the transition state that is the E-S complex through temporary interactions with the substrate.
Enzymes also help in bringing the reactant molecules into a proper orientation to increase the chances of effective collisions. Mostly, enzyme catalysis involves acid-base catalyzed reactions in which protons are donated or accepted, or are covalently catalyzed.
The Enzyme Kinetics
The rate of enzyme reaction is directly proportional to the substrate concentration because, as the substrate concentration increases, due to the continuous formation of the E-S complex, the rate of enzyme-catalyzed reaction also increases. When the substrate concentration is higher, the reaction eventually reaches a point where all the active sites of the enzymes are occupied. In this stage, the reaction proceeds at its maximum velocity, called Vmax, and further addition of substrate will not increase the rate of reaction. This is illustrated in the Michaelis-Menten equation explaining the relationship between substrate concentration and rate of reaction.
What are the factors that affect Enzyme Action?
- Temperature: The activity of the enzyme increases as the temperature rises up to an optimum temperature, then decreases due to denaturation of the protein.
- pH: Each enzyme works under an optimum pH. If there are any deviations, then the active site of the enzyme would be affected due to ionization.
- Substrate concentration: A rise in substrate concentration will increase the reaction rate until all the enzyme’s active sites are saturated.
- Enzyme concentration: A higher enzyme concentration will increase the rate of reaction if there is an abundant substrate.
- Presence of inhibitors: If there are any inhibitors, then the reaction rate will be interfered with because the inhibitor will block the active site or bind to some other site and causing changes in the active site and hindering the binding of substrate with the enzyme.
Industrial and Medical Importance
Enzymes are used as environmentally benign catalysts to accelerate chemical reactions. They are widely used in processes including fermentation, food production, and chemical synthesis in the food and pharmaceutical industries. Enzymes are also essential in biosensors and diagnostics, where they aid in the accurate identification and tracking of biological substances.
Biochemical reactions are accelerated by enzymes, which are extremely effective chemical catalysts. Chemical concepts like kinetics and catalysis can be used to understand their mechanism. Enzymes are essential for maintaining life and guaranteeing the correct operation of biological systems because they allow reactions to happen quickly under mild conditions.
