an aliphatic polyunsaturated liquid hydrocarbon with the formula C30H50. Squalene, which boils at 242°C and is soluble in many organic solvents, is an important intermediate in the metabolism of triterpenoids and steroids and is widely distributed in the tissues of animals and plants, as well as in microorganisms. It was first isolated from the liver of the shark. The biosynthesis of squalene is from mevalonic acid, which is converted to farnesyl pyrophosphate. The latter, under the action of squalenesynthetase (in the presence of thiamine), is di-merized to yield squalene. The enzymatic conversion of squalene to lanosterol and of lanosterol to cholesterol and other sterols commences with the aerobic oxidation of the terminal double bond of squalene.