Question

a) What are enzymes?
b) Discuss the mechanism of enzyme action.

Answer 1

Enzyme is a substance produced by living organisms. It acts as a catalyst which helps to carry out specific reactions. They speed up the rate of chemical reactions. They are also present in our body and help regulate complex reactions in our body.

Complete answer:
An enzyme is a protein or RNA produced by living cells. They are important biological catalysts. The term ‘enzyme’ was coined by Fredrich Wilhelm in 1878. It was earlier called ‘ferments’. Enzymes require a specific site to bind with the substrates as substrate molecules are smaller than enzyme molecules. These sites are called ‘active sites’.
According to the types of reactions enzymes are categorized in 7 types: oxidoreductase, transferase, hydrolase, lyase, isomerase, ligase, translocase.
It has various properties such as:

they are highly specific; they bind to specific substrates and catalyze a single reaction.
they remain unchanged by the completion of reaction.
they do not act alone; they require cofactors to work along with.
they speed up the rate of reactions.
b) Mechanism of enzyme activity- An enzyme attaches to a substrate at the active site and catalyzes the chemical reaction by which separate products are formed and then allows the products to release from its surface. The enzyme substrate combination is called enzyme-substrate complex. Let’s understand it using an example, assume two substrates S and S’ which to the active site of an enzyme and react to form two products P and P’. these products then dissociate from the enzyme surface and the enzyme remains unchanged and is able to react with other substrates and form products. There are two kinds of enzymatic reactions, one with intermediate formation and one without.
There are various factors that affect the enzyme activity such as temperature, pH value, substrate, and enzyme concentration

Note: In an enzyme, the active site is very significant because that’s where the substrate attaches. It comes with numerous properties such as, it occupies a small portion of the enzyme, it is a 3 dimensional entity formed of amino acids, active sites bind to the substrate molecules by weaker force.