Toheed Mehrani on Instagram: "‎Definition and Function of Enzymes ‎An enzyme is a substance that acts as a catalyst in living organisms. ‎ ‎It regulates the rate of chemical reactions without being altered itself in the process. ‎ ‎Most enzymes are made up of protein. A few catalytic RNA molecules exist and are called ribozymes. ‎ ‎ ‎Enzymes work by binding a substrate at their active site to facilitate a reaction. ‎ ‎Historically, processes like the fermenting of wine, leavening of bread, curdl