| 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 |
$\begin{array}{|c|c|c|c|}\hline {} &\text { Molisch's Test} & {\text { Barfoed Test}} & {\text { Biuret Test}} \\ \hline \text { A} & { Positive } & {\text { Negative }} & {\text { Negative }} \\ \hline \text { B } & {\text { Positive }} & {\text { Positive }} & {\text { Negative }} \\ \hline \text { C } & {\text { Negative }} & {\text { Negative }} & {\text { Positive }} \\ \hline\end{array}$
$A, B$ and $C$ are respectively