Keratin in skin is softer than keratin in nail because keratin in skin has:
A i.e. Less number of disulphide bondsKeratin in skin is softer than keratin in nail, horn & hooves because skin keratin has less number of disulfide bondsQ between Cys residues of adjacent polypeptide chains.
Less number of disulphide bonds
Less number of salt bridges
High sodium content
Different affinity for water