A synthase is a specific type of enzyme that catalyzes synthetic chemical reactions, or chemical reactions in which a number of reactants combine to form a product. An enzyme is a common type of protein; different enzymes catalyze different and generally highly-specific chemical reactions that may or may not be synthetic in nature. Catalysis is a chemical process by which a catalyst reduces the energy requirements of a chemical reaction, thereby greatly speeding up the reaction. It is important to note that a catalyst is not actually consumed by a chemical reaction, so an enzyme such as synthase may catalyze the same type of chemical reaction many times.
Synthase enzymes belong to a larger family of enzymes known as ligase enzymes. A ligase is an enzyme that catalyzes the formation of new chemical bonds between previously separate molecules. While there are many different varieties of ligases, the ligase family focuses primarily on only a few different types of chemical bonds that are particularly common in biochemical reactions. Such bonds include carbon-carbon, carbon-oxygen, and carbon-nitrogen bonds. Carbon is the most important of all of the common atoms that appear in biochemical reactions within organisms, so many enzymes are devoted to ensuring that it binds properly in order to form essential organic molecules.
One example of a common and important type of synthase is adenosine triphosphate (ATP) synthase. ATP synthase is an encompassing name for any enzyme that catalyzes the synthesis of ATP, one of the most important energy-containing molecules used in cellular metabolism. ATP is formed through the synthesis of adenosine diphosphate or adenosine monophosphate and one or more inorganic phosphate groups. ATP synthase catalyzes the synthesis of these molecules, greatly reducing the energy barrier of the reaction and making ATP synthesis energetically feasible. Some energy is still required in order for the synthesis reaction to occur, but the presence of an enzyme ensures the energy requirement does not prevent the reaction from proceeding at the appropriate rate.
Synthases and other enzymes are commonly studied in biochemistry, biology, and organic chemistry, as their precise roles in many important chemical processes are still not fully understood. Enzymes such as synthase are very important in the health sciences, as many of the reactions they catalyze are important to the cause or prevention of various diseases and illnesses. Learning their particular mechanisms of action may allow health scientists to enhance or restrict their actions in order to fight such illnesses.