An enzyme is a protein that acts as a biological catalyst. It decreases the amount of energy needed (activation energy) to start a metabolic reaction. Different enzymes work in different environments due to changes in temperature and acidity. For example, the amylase that is active in the mouth cannot function in the acidic environment of the stomach; pepsin, which breaks down proteins in the stomach, cannot function in the mouth. Without enzymes, the stomach would not be able to harvest energy and nutrients from food.
People often associate the word “carbohydrates” with a fatty diet that makes one overweight, but sensible intake of carbs is an essential source of energy. © iStockphoto.com/Maica.