1. Temperature: Enzyme activity increases with increasing temperature, but is destroyed at higher temperatures. The best temperature for enzymes is 35-400C. 00C. Most enzymes are inactivated by heat. The temperature is 450C. Above this, the enzyme denatures or denatures.
2. Water: Enzymes are inactive in the absence of water. Increasing the amount of water increases the rate of enzyme action.
3. pH : Enzyme activity is controlled by pH. The optimum pH of enzymes is trypsin-8.0, urease-7.0, cellubiase-5.0, invertase-4.5, pepsin-2.0 etc.
4. Substrate concentration: Enzyme activity increases as substrate concentration increases and enzyme activity decreases as substrate concentration decreases.
5. Enzyme concentration: Increase in enzyme concentration increases the rate of reaction and decrease in enzyme concentration decreases the reaction.
6. Co-enzymes: Enzyme activity increases in the presence of any co-enzyme. Eg ATP, ADP, NAD, NADP, FAD, FADP etc.
7. Metals or metals: The presence of metals both increases and decreases enzyme activity. Enzyme activity increases in presence of Mg2+, Mn2+ etc.
8. Oxidation: Some enzymes are activated by oxidation and are inactivated by exposure to mild oxidizing agents. For example, sulfhydryl.
9. Inhibitors: The presence of substances that temporarily or permanently stop the action of enzymes are called inhibitors. High energy radiation, salts of heavy metals, cyanide, dinitrophenol, formalin etc. are inhibitors.
10. Activator: Activator activates the inactive enzyme. Inactive pepsinogen is converted to active pepsin under the influence of HCl. Like Cl+, Mg++, Ca++, Mn++ etc.
11. Contact: Enzyme and substrate come into contact with each other and form compounds. Enzyme action occurs when the compound is formed.
12. Irradiation: High energy radiation (α, β and γ rays) causes structural deviation of the enzyme and reduces the activity.
13. Inhibiting agents: Metals whose presence inhibits enzyme activity are called inhibitory agents. Like Ag, Zn, Hg, Cu etc.