Mechanism of Enzyme Action

The catalysing of biochemical reactions in our bodies is enhanced by the proteinaceous molecules called enzymes. Enzymes are also called biocatalysts due to this property. The enzymes may also possess secondary and tertiary structures as they are proteinaceous in nature. The enzymes are termed active when they are present in their tertiary structure. This happens when the protein chain gets folded upon itself. The main factor behind the mechanism of enzyme action is these active sites. Also, these sites are responsible for the mechanism of enzyme catalysis. The further article explains the mechanism of enzyme action.

Structure of Enzymes:

Enzymes are usually present in almost all cells and organs of animals and humans. The enzymes are usually three-dimensional in structure and consist of chains of amino acids. Except for the enzymes related to RNA, all of them are comprised of proteins. Enzymes tend to lose their function when the temperature of pH increases or decreases. This is because they are sensitive to pH and temperature. 

Mechanism of Enzyme action:

The human body comprises many complex tissues and organs to make it work smoothly. Certain chemicals are released in the body that enhance its mechanism. These chemicals are called enzymes. The enzymes control biological processes like reproduction, excretion, respiration, digestion, etc. These processes are vital for all living beings, whether humans or animals. The proteinaceous structure of the catalysts helps to smoothen these processes. 

The very first step that describes the mechanism of enzyme action is the interaction of the enzyme with the substrate. This interaction triggers the initial stage of biological activity in our body.

Furthermore, their process leads to the formation of “products”.

Enzyme type and functions:

Nature of Enzyme action:

An enzyme-substrate complex is formed when the substrate comes in contact with the active site of the enzymes.

There is a change from the enzyme-substrate complex into the enzyme-product complex, and after this, the product gets separated from this complex. Thus, the enzyme is not used up in the reaction but rather helps in its enhancement. The following points explain the catalytic cycle in a much easy manner-

• The substrate is triggered towards the enzyme’s active site.
• An alteration in the shape of the enzyme is observed.
• Bonds make and break, and the enzyme-product complex is formed.
• The product is finally separated from the complex leaving behind the enzyme, which can now again be used to catalyse other processes.

Factors affecting the mechanism of Enzyme action:

The following factors describe the mechanism of enzyme action more clearly:

1. TEMPERATURE

The enzymes are sensitive to temperature changes. They only work efficiently in a narrow range of temperatures. A high temperature leads to denaturing the structure of enzymes, and the enzyme becomes inactive when the temperatures are low. The enzyme shows the highest catalytic activity at optimum temperature. 

2. HYDROGEN ION CONCENTRATION

Along with an optimum temperature, an optimum pH level is also required for the enzyme to function properly.  The activity of any enzyme reduces if there is any rise or fall in the pH level. However, the catalytic activity is maximum at optimum pH. Some enzymes show good catalytic behaviour in alkaline medium, while others may do so in acidic medium. 

3. SUBSTRATE CONCENTRATION

Substrate is a compound that reacts with the active sites of enzymes to form substrate-enzyme compounds, which further changes to product-enzyme complexes, which at the end releases the final product leaving behind the enzyme. The velocity of enzyme action increases with an increase in the concentration of the substrate and vice-versa.

Mechanism of enzyme action in biochemistry:

Physical and chemical changes occur in chemical compounds. The change in shape or structure of the compound signifies the physical change. These changes do not include the making or breaking of bonds. In contrast, new bonds are formed and broken in chemical changes during the transformation. 

Let us take the example of the melting of ice. There is a change in state from solid to liquid in this case, so this is stated as a physical change. However, some other examples, such as hydrolysis of starch, will be stated as a chemical change. The amount of product formed per unit time in both these processes is the rate of the reactions, respectively. Velocity is defined as the rate at which the reaction takes place with respect to a certain direction. The rate of the chemical and physical processes is affected by the temperature. 

There are various types of enzymes present, and each of them differs from the other. Each has a unique chemical or metabolic reaction or unique catalytic activity.  A certain metabolic pathway is followed by each enzyme that includes various steps to catalyse any reaction. In some cases, a variety of end products formed. These are the cases where the metabolic pathway includes more than one or two additional reactions. So, this is how the mechanism of enzyme action takes place in biochemistry.

Conclusion:

From the above discussion, we can conclude that enzymes are involved in catalysing various biochemical and biological processes. The structure of enzymes is proteinaceous in nature. The mechanism of enzyme action involves four steps. In short, these steps include triggering the active site of the catalyst to the substrate, forming substrate-enzyme complexes, which in turn change into product-enzyme complexes and the final product being separated from this complex leaving behind the enzyme. The enzyme left behind is not used in the reaction and can be used again and again for new substrates.