מבוא לקינטיקה אנזימטית

Enzyme kinetics studies the rates of enzyme-catalyzed reactions. The rates of repeated experiments at varying substrate concentrations are monitored by measuring the concentration of substrate consumed or product formed over time.

These results can be graphed to show how substrate concentration affects the rate or velocity of a reaction.

The reaction velocity increases linearly with increasing substrate amounts at low concentrations, but it begins to plateau at higher concentrations. The rate approaches a maximum velocity or V_max – the rate where the enzyme is completely saturated with the substrate.

Enzyme affinity measures how strongly or weakly an enzyme binds its substrate and is quantified by K_M, the Michaelis constant. The value of K_M is equal to the substrate concentration when the rate is 50% of the V_max.

A small K_M indicates an enzyme has a high substrate affinity and vice versa. An enzyme with a larger K_M requires higher substrate concentrations to approach its maximum velocity compared to an enzyme with a lower K_M.