Coenzyme A is, not surprisingly, a coenzyme. It is also known as a cofactor. The terms cofactor and coenzyme can be used interchangeably. They are chemical compounds that are bound to proteins in the body. Without a cofactor attached, a protein cannot carry out its biological function.
Cofactors are also known as helper molecules, and are often classified according to how tightly they are bonded to their protein partner. Tightly bonded cofactors are known as prosthetic groups, and loosely bonded cofactors are typically referred to by the broader term coenzymes. The first cofactor was isolated in 1906, in yeast, but cofactors can be organic or inorganic.
The most important function of coenzyme A is to aid in oxidizing and synthesizing fatty acids. It is also used as a substrate in the enzymes of all sequenced genomes, and is used in 4% of cellular enzymes. In addition, this substance is responsible for helping to maintain the citric acid cycle, by oxidizing pyruvate. This coenzyme begins its life as pantothenate and is converted through a five-step process into a usable form.
Chemically, coenzyme A is a thiol. This means that it contains a functional group that has a sulfur-hydrogen (SH) bond. These are often referred to as thiol groups or sulfhydryl groups, but were originally known as mercaptans. Typically, a thiol has a potent odor, often similar to garlic. The lower the molecular weight of the thiol, the more intense the smell. It is a thiol, known as t-butyl mercaptan, that is used to give natural gas an odor.
Coenzyme A is produced in the body, but can also be taken as a nutritional supplement. In theory, the intake of this compound results in lower stress and slower aging, a strengthened immune system, and accelerated production of energy from fat in the body. These supplements are taken once a day in tablet or capsule form, on an empty stomach. The United States Food and Drug Administration (FDA) has not evaluated many of the claims made by commercial retailers of the substance, and limited research has been done into its effectiveness as a supplement.
Interest in using this coenzyme in chemical experiments is also on the rise, with a number of companies producing several varieties of coenzyme A for laboratory use. Originally, this compound had to be synthesized in a laboratory and required a substantial amount of time. Companies such as Sigma-Aldrich® now offer short, medium, and long chain versions of coenzyme A for purchase.