Thus they do not obey classic Michaelis-Menten kinetics. In some cases binding of substrate molecule can increase binding and activity with subsequent substrate molecules e.g., the first CO 2 molecule activates Rubisco enzyme while another CO 2 is used as substrate for carboxylation. Many enzymes require presence of cofactors for activity. They are often a way for energy input to endergonic reactions, to make them spontaneous or a source of energy from exergonic reactions. High Energy Compounds.
Enzymes only increase the rate at which equilibrium is reached.