Explain complex enzyme

All enzymes are mostly protein, but many are only protein. These enzymes are known as simple enzymes. Enzymes that contain other things, "complex enzymes," are called holoenzymes. A holoenzyme has two parts. The protein part is called the apoenzyme.

The enzyme substrate complex is a temporary molecule formed when an enzyme comes into perfect contact with its substrate ... The substrate causes a conformational change, or shape change, when the substrate enters the active site. The active site is the area of the enzyme capable of forming weak bonds with the substrate.

Enzymes are protein molecules in cells which work as biological catalysts. Enzymes speed up chemical reactions in the body, but do not get used up in the process, therefore can be used over and over again. Almost all biochemical reactions in living things need enzymes ... The study of enzymes is called enzymology.