Figure 4.

Schematic representation of binding region and catalytic site of a protease. This hypothetical protease possesses six subsites (S₁-S₃ and S₁’-S₃’) in its catalytic site and, consequently, is able to recognize and bind to a sequence of six amino acids (P₁-P₃ and P₁’-P₃’) in the proteinaceous substrate. After proteolysis, at least two smaller peptides are generated as the reaction products.