Enzymes react with substrates as part of the biological chemical processes that take place in human bodies, and their role in triggering these interactions is the basis of the descriptive term biological catalysts. Without the catalytic action of the enzymes, the products that human bodies require to produce energy do not form quickly enough.
A catalyst drives a chemical reaction forward. One of the ways this is accomplished is through a catalysts ability to lower the activation energy required for a reaction to occur. By doing so, the catalyst enables two molecules to cross the kinetic barrier and form new products.