| Item $I$ | Item $II$ |
| $A$ Allosteric effect | $P$ Molecule binding to the active site of enzyme |
| $B$ Competitive inhibitor | $Q$ Molecule crucial for communication in the body |
| $C$ Receptor | $R$ Molecule binding to a site other than the active site of enzyme |
| $D$ Poison | $S$ Molecule binding to the enzyme covalently |