Dehydratase is an enzyme that catalyzes the removal of oxygen

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 and hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 from organic compound

Organic compound

An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

s in the form of water. This process is also known as dehydration

Dehydration

In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...

.

There are four classes of dehydratases:

1. Dehydratases acting on 3-hydroxyacyl-CoA esters (no cofactors)

2. Dehydratases acting on 2-hydroxyacyl-CoA esters (radical reaction, [4Fe-4S] cluster containing)

3. Dehydratases acting on 4-hydroxyacyl-CoA esters ([4Fe-4S] and FAD containing)

4. Dehydratases containing an [4Fe-4S] cluster as active site (aconitase, fumarase, serine dehydratase)