Enzymes

This chapter discusses the role of enzymes as catalysts, mechanisms of enzyme catalysis, coenzyme catalysis, and enzyme therapy. Enzymes are natural proteins that catalyze chemical reactions. Most enzymes are soluble and found in the cytosol of cells. They interact with substrates to form enzyme–substrate complexes, thereby transforming the substrates into products. Enzymes function by lowering transition state energies and energetic intermediates and by raising the ground state energy. The transition state for an enzyme-catalyzed reaction is a high-energy state with a lifetime of about 10 -13 sec, the time for one bond vibration. Once the substrate binds to the active site of the enzyme, there are a variety of mechanisms that the enzyme can utilize to catalyze the conversion of the substrate to product.. Some enzymes are useful as drugs, and such enzymes have therapeutic utility to catalyze hydrolytic reactions. The use of genetic engineering techniques to produce altered active enzymes has enhanced the use of enzymes as drugs. The major drawbacks to use the enzymes in therapy are enzyme instability and allergic responses.