Chapter 23.1, Problem 4SSC

Interpretation Introduction

Interpretation:

The process by which properties of protein make them such useful catalysts should be determined. The point by which they are different from other catalysts should be determined.

Concept introduction:

Proteins are polymeric biomolecules which are formed by the polymerisation of amino acids. Amino acids are the organic molecules with $–{\text{NH}}_{\text{2}}$ and −COOH functional groups bonded on same carbon atom of the molecule.

They polymerise by peptide linkage to form dipeptide, oligopeptide and polypeptide molecules. Each peptide bond formation is a condensation reaction that occurs with the elimination of water molecule.

Explanation of Solution

Proteins show the function of enzymes as well. The biological molecules which speed up the rate of a chemical reactions takes place in cells are known as enzymes. The enzyme region where molecules of the substrate binds and perform a chemical reaction is known as an active site. The active site of an enzyme composed of residues of amino acids which form temporary bonds with the binding site that is substrate and the shape of substrate changes by forming enzyme-substrate complex. Due to large size of enzymes, they can able to form multiple bonds with binding site (substrate). The forces formed between enzyme (amino acid chains) and substrate lower the activation energy. Thus, the ability of protein to bind with other species makes protein useful catalyst.

The difference between proteins (enzymes) and other catalyst is that the enzymes are organic in nature and also known as biocatalyst whereas other catalyst can belongs to inorganic in nature. Enzymes are complex proteins and only results in the speed up of reaction whereas catalyst increase as well as decrease the rate of reaction.