Protein-protein interaction (PPI) is a highly specific physical contact established between two or more protein molecules, which results from biochemical events generated by the interaction. These interactions include electrostatic forces, hydrogen bonding and hydrophobic effect. Many are physical contacts of molecular associations that occur in cells or living organisms in a specific biomolecular environment. CD ComputaBio provides corresponding PPI network service. Our PPI network service have proven to be very useful for understanding the biochemical basis of physiological events at different stages of drug development (even in different fields such as materials science).