Enzyme kinetics is important for understanding how enzymes work in different situations. Two key things that affect how well enzymes do their job are the amount of substrate and enzyme inhibitors.

1. Substrate Concentration:

   • When you increase the amount of substrate, the speed of the reaction also goes up, but only until it hits a maximum speed called $V_{max}$.
   • We can use a formula called the Michaelis-Menten equation to explain this speed: $v = \frac{V_{max}[S]}{K_m + [S]}$
   • In this formula, $[S]$ is the amount of substrate, and $K_m$ (Michaelis constant) is the amount of substrate needed for the reaction speed to be half of $V_{max}$. For many enzymes, the $K_m$ values can be very low (micromolar) to moderately high (millimolar).

2. Enzyme Inhibition:

   • Enzyme inhibitors are substances that can slow down enzyme activity. They do this by attaching to the enzyme, which can lower $V_{max}$ or change the $K_m$ value.
   • There are different types of inhibition:
     • Competitive inhibitors increase $K_m$,
     • Non-competitive inhibitors lower $V_{max}$,
     • Uncompetitive inhibitors decrease both $V_{max}$ and $K_m$.
   • For example, a competitive inhibitor can raise the $K_m$ by up to 10 times, which can affect how drugs are given and how effective they are.

Knowing about these factors is important for making enzyme tests better in medical biochemistry.