This page explains what enzymes are and how their chemical reaction rates can be predicted by math functions. Enzymes are protein catalysts that can speed up chemical reactions by lowering activation energy required. They are not only used in science experiments, but also broadly used by living organisms for cellular processes. This site explains how reaction rate depends on the concentration of substrate at a fixed enzyme concentration. The rate of product formation can be determined by monitoring the rate that substrate disappears. This can be useful in chemistry experiments.