Enzyme Notes

Enzymes are proteins that act as biological catalysts. A catalyst is a substance that speeds up chemical reactions and remains unchanged by the reaction. The chemical reactions that are necessary to support life could not occur without enzymes. These chemical reactions are too slow or require too much activation energy. Consequently enzymes allow the body’s chemical processes to work more efficiently.

Chemical reactions involve building or breaking compounds. In your saliva there is the enzyme Amylase. Amylase breaks down the starch molecule called Amylum into simple sugars that your body can use as energy. Compounds like Amylum are held together with chemical bonds that store energy. Thus, in a chemical reaction, energy is either released or absorbed. In order for most chemical reactions to occur, a level of energy must be present to get the reaction started. This energy is called activation energy.

Enzymes work by lowering the activation energy needed to start a chemical reaction. Therefore, enzymes speed up chemical reactions. How do they do this?

The structure of enzymes provides a more energetically favorable environment for compounds to react. The shape of an enzyme has a specific area that attaches to the chemical compound undergoing the change. The area where the chemical attaches is called the active site. The active site of an enzyme is similar to a jigsaw puzzle piece where only one specific piece will fit.

The substance that fits into the enzyme is called a substrate. The enzyme holds the substrate in position, allowing a chemical reaction occur. When the chemical reaction is complete, the enzyme releases the products and the enzyme remains unchanged. The enzyme is then able to assist with the same chemical reaction over and over again. The unique structure of enzymes is coded by the DNA of the cell. The structure determines the function of the enzyme. This makes enzymes specific to the chemical reaction they catalyze.