Proteins are one of the most fundamental compounds that build living organisms. Various side chains of amino acids (mers in these biopolymers) enable multiple intra-and intermolecular interactions such as the Coulombic and van der Waals forces, aromatic π-π and ion-mediated salt bridges. Interactions between proteins are combinations of several attractive and repulsive forces between chemical groups of amino acids oriented properly to maximise attractive forces and minimise repulsive ones. Protein interactions often result in a conformational change in the tertiary protein structure, which regulates enzyme activity, opening channels or enabling motor activity. Understanding these interactions and their description measurably and comparably is a continuous aim of biochemistry and molecular biology.