Proteins are of different types based on the polypeptide chain.
(i) Monomeric protein : The protein which is made up of one polypeptide chain is called monomeric protein. For example, myoglobin.
(ii) Dimeric protein : The protein which is composed of two polypeptide chains is called dimeric protein. eg transamylase.
(iii) Trimeric protein : The protein which is made up of three polypeptide chains is called trimeric protein. For example, Hemerythrin.
(iv) Tetrameric protein: Proteins which are made up of four polypeptide chains are called tetrameric proteins. For example, hemoglobin.
(v) Polymeric protein: Proteins which are made up of several polypeptide chains are called polymeric proteins. For example, insulin.