The human cell contains about 1300 varieties of enzymes that catalyze hundreds of thousands of different reactions to help the body and senses to function. Enzymes require optimum pH and temperature to function correctly. For example, if your stomach doesn’t produce enough acid, pepsin wouldn’t be able to break down the macromolecules into proteins. Some of the commonly found enzymes in the human body are amylase, lactase, lipase, Maltase, peptidase, gelatinase, and protease.