The process of formation of complex protein:-Protein complex: It is formed when two or more polypeptide chain are interconnected they form non-covalent interaction between two protein. In the process protein complex formation it includes an encounter complex, where protein have specific interaction and take many orientations, they have two types of interaction one is electrostatic interaction and hydrophobic interaction play an important role.T he protein remain soluted during the encounter phase.The protein forms an encounter complex in very extreme care and the encounter state consist of a significant in many different care which implies that there is small energy difference between encounter and productive complex. Therefore, in protein complex, the encounter complex implies the essential part.