enzymology An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

, a 4-hydroxy-3-methylbut-2-en-1-yl diphosphate synthase (HMB-PP synthase, IspG, ) is an

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

that

catalyzes Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...

the

chemical reaction A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...

:2-C-methyl-D-erythritol 2,4-cyclodiphosphate + protein-dithiol

\rightleftharpoons

(E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate + H₂O + protein-disulfide The

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ...

of this enzyme is 2-C-methyl-D-erythritol 2,4-cyclodiphosphate (MEcPP) and the product is (E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate (HMB-PP). Electrons are donated by two reduced

ferredoxin Ferredoxins (from Latin ''ferrum'': iron + redox, often abbreviated "fd") are iron–sulfur proteins that mediate electron transfer in a range of metabolic reactions. The term "ferredoxin" was coined by D.C. Wharton of the DuPont Co. and applied t ...

proteins per reaction. This enzyme participates in the MEP pathway (non-mevalonate pathway) of

Isoprenoid The terpenoids, also known as isoprenoids, are a class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeably with "terpene ...

precursor biosynthesis.

Nomenclature

This enzyme belongs to the family of

oxidoreductase In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually ut ...

s, specifically those acting on CH or CH₂ groups with a disulfide as acceptor. The

systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivi ...

of this enzyme class is (E)-4-hydroxy-3-methylbut-2-en-1-yl-diphosphate:protein-disulfide oxidoreductase (hydrating).

Nomenclature

References

Further reading