The

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...

''ent''-kaurene synthase (EC 4.2.3.19)

catalyzes Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycl ...

the

chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and break ...

:''ent''-copalyl diphosphate

\rightleftharpoons

''ent''-kaurene + diphosphate This enzyme belongs to the family of

lyase In biochemistry, a lyase is an enzyme that catalyzes the breaking (an elimination reaction) of various chemical bond A chemical bond is a lasting attraction between atoms or ions that enables the formation of molecules and crystals. The bon ...

s, specifically those carbon-oxygen lyases acting on phosphates. 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 semitrivial ...

of this enzyme class is ''ent''-copalyl-diphosphate diphosphate-lyase (cyclizing, ''ent''-kaurene-forming). Other names in common use include ''ent''-kaurene synthase B, ''ent''-kaurene synthetase B, ''ent''-copalyl-diphosphate diphosphate-lyase, and (cyclizing). This enzyme participates in diterpenoid biosynthesis.

In ''Stevia''

In ''

Stevia Stevia () is a natural sweetener and sugar substitute derived from the leaves of the plant species '' Stevia rebaudiana'', native to Paraguay and Brazil. The active compounds are steviol glycosides (mainly stevioside and rebaudioside), wh ...

'' spp., ''ent''-kaurene synthase is a required part of the biosynthesis of

steviol Steviol is a diterpene first isolated from the plant '' Stevia rebaudiana'' in 1931. Its chemical structure was not fully elucidated until 1960. Steviol occurs in the plant as steviol glycosides, sweet compounds that have found widespread use ...

. Hajihashemi ''et al.'', 2013 find that it is involved in the drought stress response and because it mimics drought stress

paclobutrazol Paclobutrazol (PBZ) is the ISO common name for an organic compound that is used as a plant growth retardant and triazole fungicide. It is a known antagonist of the plant hormone gibberellin, acting by inhibiting gibberellin biosynthesis, reduc ...

toxicity. Both inhbit

transcription Transcription refers to the process of converting sounds (voice, music etc.) into letters or musical notes, or producing a copy of something in another medium, including: Genetics * Transcription (biology), the copying of DNA into RNA, the fir ...

steviol glycoside Steviol glycosides are the chemical compounds responsible for the sweet taste of the leaves of the South American plant ''Stevia rebaudiana'' (Asteraceae) and the main ingredients (or precursors) of many sweeteners marketed under the generic name ...

synthesis genes including ''ent''-kaurene synthase. This is believed to reduce steviol content in the final plant product.

References

* * * * EC 4.2.3 Enzymes of unknown structure {{4.2-enzyme-stub