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EC 4.2.3.108 Details
EC number
4.2.3.108
Accepted name
1,8-cineole synthase
Reaction
geranyl diphosphate + H2O = 1,8-cineole + diphosphate
Other name(s)
1,8-cineole cyclase,
geranyl pyrophoshate:1,8-cineole cyclase,
1,8-cineole synthetase
Systematic name
geranyl-diphosphate diphosphate-lyase (cyclizing, 1,8-cineole-forming)
CAS registry number
110637-19-9
Comment
Requires Mn2+ or Zn2+. Mg2+ is less effective than either. 1,8-Cineole is the main product from the enzyme with just traces of other monoterpenoids. The oxygen atom is derived from water. The reaction proceeds via linalyl diphosphate and α-terpineol, the stereochemistry of both depends on the organism. However neither intermediate can substitute for geranyl diphosphate. The reaction in Salvia officinalis (sage) proceeds via (–)-(3R)-linalyl diphosphate [1-3] while that in Arabidopsis (rock cress) proceeds via (+)-(3S)-linalyl diphosphate [4].
History
created 2012
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