Enzymes are globular proteins with an active site and act as a biological catalyst. Enzyme catalysts are categorized under six major types: oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases. Although many enzymes have similar names, they are acquired from different organisms. In addition, these enzymes have different catalytic activity, e.g., glucose isomerase. The protein structure of an enzyme is responsible for the catalytic ability. One must understand the significance of active sites as they are important in explaining the science behind enzyme kinetics. The actual working of enzymes was unknown to people although they used enzymes for preparing different food products for a long time. Enzymes have been used for making cheese from milk, extracting and clarifying fruit juices, tendering meat or animal protein, processing raw plants, and reducing the maturation time for wine making. Commercially, enzymes have been used since the late 19th century.