Define the following as related to proteins : (3 marks)
(i) Peptide linkage (ii) Primary structure (iii) Denaturation
(i) Peptide linkage : A peptide linkage is an amide linkage formed between group of
-amino acid and group of the other -amino acid by loss of a molecule of water. The
bond formed is called petide linkage.
(ii) Primary structure : Proteins may have one or more polypeptide chains. Each polypeptide in a
protein has amino acids linked with each other in a specific sequence and it is this sequence of
amino acids that is called the primary structure of that protein.
(iii) Denaturation : Due to coagulation of globular protein under the influence of change in tem-
perature, change in pH etc., the native shape of the protein is destroyed and biological activity
is lost and the formed protein is called denaturated proteins and the phenomenon is denatura-