Enzyme Catalysis

The substance that alters the rate of reaction but itself remains chemically unchanged at the end of the reaction is known as a catalyst. A small amount of the catalyst is required, for example, one mole of colloid Pt catalyst. The catalyst generally does not change the equilibrium constant, but the equilibrium approach earlier. A catalyst is specific in nature. It means, by the change of catalyst, the nature of the product changes or specific catalyst for a specific reaction. Almost all the enzymes have 3D structures, for example, the globular protein. There are some unique RNA specialities that can also act as enzymes known as  Ribozymes.

Enzyme Catalysis

Enzymes are biological catalysts reactions and reduce the enzyme activity of a wide range of biological activities. They do this by attaching the reactant, termed substrate, to the enzyme’s active site. The substrate can form an activated compound at the active site at a lower energy level. After the reaction is completed, the product leaves the active site, allowing the enzyme to catalyse other reactions. By attaching to a substrate, the active site of an enzyme catalyses a biological process. When the reaction is complete, the products are released, and the enzyme can now catalyse additional reactions. Most developments are in moderate reaction conditions for almost complex and unstable molecules, the desired biocompatible of a enzyme (catalyst) to support environmental chemistry, safe and environmentally aspect, ability to minimise or remove reaction besides, and the ability to carry out a classical multistage reaction in a single step.

Type of Catalysis 

Heterogeneous catalysis: Catalysts with different phases as the reactant; they are usually in the solid-state; for example, decomposition of H2O2 with MnO2 as catalyst and hydrogenation of ethene (Ni as a catalyst).

Homogeneous catalysis: Catalysts that remain the same in the reactant; they are usually in an aqueous state.

Autocatalysis: The product in the reaction is the catalyst of the reaction, and the product is known as an autocatalyst.

Positive catalyst: The catalyst which increases the rate of a chemical reaction is called a positive catalyst, and the phenomenon is known as positive catalysis; for example, H2O2   pt→   H2O  + O.

Negative catalyst: The catalyst which decreases the rate of a chemical reaction is called a negative catalyst, and the phenomenon is known as negative catalysis.

Examples: (i)  H2O2   →   H2O  + O

                  (ii) Knocking of the petrol by tetraethyl lead

Enzyme Catalysis

Enzymes function as biological catalysts. We can take a number of examples in which enzymes are made by living cells.

The enzyme catalysis breaks down the unwanted substance:

Substrate + Enzyme ⇆  Product 

Enzyme Characteristics

• It speeds up the reaction.
• It’s made up of proteins.
• They are specific in properties.
• In the reaction, it won’t be used more.
• They must be in the finest possible condition in order to function properly.
• They get denatured at high temperatures.

Mechanism of Enzyme Catalysis

Enzymes are biological molecules, and they are highly selective catalysts. 

                                    E + S → ES  →  P

The substance by which the enzyme is going to act is called the substrate. The enzyme molecule has a protein chain that acquires a shape such that the substrate is going to fit into its structure, somewhat like a lock-and-key arrangement. The enzyme molecule, E, binds the substrate, S, into the active sites of its structure, forming an enzyme-substrate complex, ES, and the catalysis occurs, and it’s going to perform the following steps:

(a) An enzyme can link two molecules together.

(b) An enzyme has the ability to change the structure of a molecule.

In effect, the enzyme’s active site “recognises” the substrate. This explains how enzymes differ in their specificity. The enzyme-substrate combination subsequently disintegrates to yield the product, P, and the enzyme is regenerated and ready to react with another molecule of substrate. The mechanism is depicted as: 

                                       E + S →  ES + P + E

The creation of the enzyme-substrate combination opens up a new, lower-energy route. When inhibitors occupy the active sites or the temperature rises due to the loss of the enzyme’s structure (it is a protein), the catalytic function of the enzyme is lost.

Conclusion

Enzyme catalysis accelerates the chemical reaction without participating in the chemical reaction. Enzyme catalysis is a type of catalysis that uses enzymes as a catalyst. The properties of enzymes and the mechanism of enzyme catalysts are very useful for us to understand catalysts, which were discussed in this article. Enzymes are chemicals that speed up a chemical process by decreasing the activation energy. They are, however, unaffected or unaltered by the response. Catalysts can be either inorganic or organic. Metal ions or tiny molecules that accelerate chemical processes in living beings are examples of inorganic catalysts.