CHEMISTRY OF PROTEOLYSIS

Explanations have been put forward on the basis of the dipole moments of C—H, C—C, N-H bonds for the enzymatic breakdown of protein molecules.

The observed fact that proteolysis is favoured in the vicinity of an aromatic ring, is suggested to be due to the property of this group to induce polarity in the neighbouring carbon atom. Conditions that would fail to induce polarity, would retard the process of hydrolysis.

The function of enzyme is to form an activated complex with protein and then to ionise the —CONH­ linkage by induced polarity. This complex reacts with H⁺ and OH^- until equilibrium is established. The lowering of energy of activation in the process of proteolysis is accounted for by the work done in bringing the (OH^-) within the range of action of the peptide linkage against the potential of the field.

Presence of amino-acids of opposite rotatory power to that met with in nature inhibits the action of pepsin. This is due to a change in the planer position of different groups which probably fails to induce polarity at —CONH— linkage. The effect of steric hindrance appears to be energetic rather than geometrical in nature.