Polypeptides with fewer amino acids are likely to be called
proteins if they ordinarily have a well defined conformation of a protein such
as insulin which contains 51 amino acids Proteins can be classified into two types on the basis of their
molecular shape (a) Fibrous proteins
When the polypeptide chains run parallel and are held together by
hydrogen and disulphide bonds, then fibre– like structure is formed Such
proteins are generally insoluble in water