Question

The active site of an enzyme is situated in its amino acids
A. Amino groups
B. Carboxyl groups
C. K – groups
D. All of these

Answer 1

Hint: An enzyme is made up with many amino acids and two amino acids are connected by a peptide bond.
Peptide bond is formed between a carboxyl group of an amino acid with the amino group of next amino acid.

Complete answer: Active site of an enzyme can be defined as the site which is generally bound to the substrate by forming varieties of bonds.
The bonds include hydrophobic interactions, hydrogen bonds, ionic bond, Vander Waals bond etc.
The active site is present on K – groups of side groups of amino acids of an enzyme.

Additional information: Enzymes catalyze the chemical reactions by lowering its activation energy.
Increment of the temperature generally increases the rate of reaction up to a certain level. This is called optimum temperature. Optimum temperature for most enzymes is 370 C. When the temperature falls down, the enzymes get inactive and when temperature rises above 550 C, the enzymes get denatured.
Increasing the pH generally increases the rate of reaction up to a certain level. This is called optimum pH. Optimum pH for most enzymes is 5-8.
Both the effect of temperature and pH shows a bell shaped curved against rate of reaction.

So the correct answer is option C. K – groups.

Note: Active site which helps an enzyme to bind with its substrate. This portion of the enzyme is flexible, that is it can change its shape according to the substrate it is going to bind – which is the basis of the induced fit model of enzyme activity.