Statement I : Haemoglobin is an example of quaternary structure ofProteins.\ Statement II : Haemogl

Question

Statement I : Haemoglobin is an example of quaternary structure ofProteins.\ Statement II : Haemoglobin molecule is composed of four polypeptide chains-two $\alpha$-chains and two $\beta$-chains.\

Professor PC Thomas Classes · Answer

(a) :Proteins are said to have quaternary structure if they consist of 2 or more polypeptide chains united by forces other than covalent bonds (i.e., not peptide or disulphide bonds). The forces that stabilise these aggregates are hydrogen bonds and electrostatic bonds formed between amino acids on the polypeptide chains. Haemoglobin, the oxygen-transporting protein of blood, is an example of quaternary structure. This protein consists of four peptide chains of two types- $\alpha$ and $\beta$ chains that occur in pairs.