EC 4.2.1.133     
Accepted name: copal-8-ol diphosphate hydratase
Reaction: (13E)-8α-hydroxylabd-13-en-15-yl diphosphate = geranylgeranyl diphosphate + H2O
Glossary: (13E)-8α-hydroxylabd-13-en-15-yl diphosphate = 8-hydroxycopalyl diphosphate
Other name(s): CcCLS
Systematic name: geranylgeranyl-diphosphate hydro-lyase [(13E)-8α-hydroxylabd-13-en-15-yl diphosphate-forming]
Comments: Requires Mg2+. The enzyme was characterized from the plant Cistus creticus subsp. creticus.
References:
1.  Falara, V., Pichersky, E. and Kanellis, A.K. A copal-8-ol diphosphate synthase from the angiosperm Cistus creticus subsp. creticus is a putative key enzyme for the formation of pharmacologically active, oxygen-containing labdane-type diterpenes. Plant Physiol. 154 (2010) 301–310. [PMID: 20595348]
[EC 4.2.1.133 created 2012]
 
 
EC 4.2.3.140     
Accepted name: cis-abienol synthase
Reaction: (13E)-8α-hydroxylabd-13-en-15-yl diphosphate = cis-abienol + diphosphate
Glossary: cis-abienol = (12Z)-labda-12,14-dien-8α-ol
(13E)-8α-hydroxylabd-13-en-15-yl diphosphate = 8-hydroxycopalyl diphosphate
Other name(s): Z-abienol synthase; CAS; ABS
Systematic name: (13E)-8α-hydroxylabd-13-en-15-yl-diphosphate-lyase (cis-abienol-forming)
Comments: Isolated from the plants Abies balsamea (balsam fir) [1] and Nicotiana tabacum (tobacco) [2].
References:
1.  Zerbe, P., Chiang, A., Yuen, M., Hamberger, B., Hamberger, B., Draper, J.A., Britton, R. and Bohlmann, J. Bifunctional cis-abienol synthase from Abies balsamea discovered by transcriptome sequencing and its implications for diterpenoid fragrance production. J. Biol. Chem. 287 (2012) 12121–12131. [PMID: 22337889]
2.  Sallaud, C., Giacalone, C., Topfer, R., Goepfert, S., Bakaher, N., Rosti, S. and Tissier, A. Characterization of two genes for the biosynthesis of the labdane diterpene Z-abienol in tobacco (Nicotiana tabacum) glandular trichomes. Plant J. 72 (2012) 1–17. [PMID: 22672125]
[EC 4.2.3.140 created 2012]
 
 
EC 4.2.3.141     
Accepted name: sclareol synthase
Reaction: (13E)-8α-hydroxylabd-13-en-15-yl diphosphate + H2O = sclareol + diphosphate
Glossary: sclareol = (13R)-labd-14-ene-8α,13-diol
(13E)-8α-hydroxylabd-13-en-15-yl diphosphate = 8-hydroxycopalyl diphosphate
Other name(s): SS
Systematic name: (13E)-8α-hydroxylabd-13-en-15-yl-diphosphate-lyase (sclareol-forming)
Comments: Isolated from the plant Salvia sclarea (clary sage). Originally thought to be synthesized in one step from geranylgeranyl diphosphate it is now known to require two enzymes, EC 4.2.1.133, copal-8-ol diphosphate synthase and EC 4.2.3.141, sclareol synthase. Sclareol is used in perfumery.
References:
1.  Caniard, A., Zerbe, P., Legrand, S., Cohade, A., Valot, N., Magnard, J.L., Bohlmann, J. and Legendre, L. Discovery and functional characterization of two diterpene synthases for sclareol biosynthesis in Salvia sclarea (L.) and their relevance for perfume manufacture. BMC Plant Biol. 12:119 (2012). [PMID: 22834731]
[EC 4.2.3.141 created 2013, modified 2017]
 
 
EC 4.2.3.190     
Accepted name: manoyl oxide synthase
Reaction: (13E)-8α-hydroxylabd-13-en-15-yl diphosphate = manoyl oxide + diphosphate
Glossary: (13E)-8α-hydroxylabd-13-en-15-yl diphosphate = 8-hydroxycopalyl diphosphate
manoyl oxide = (13R)-8,13-epoxylabd-14-ene
Other name(s): GrTPS6; CfTPS3; CfTPS4; MvELS
Systematic name: (13E)-8α-hydroxylabd-13-en-15-yl-diphosphate diphosphate-lyase (manoyl-oxide-forming)
Comments: Manoyl oxide is found in many plants. This enzyme has been isolated from the plants, Grindelia hirsutula (gum weed), Plectranthus barbatus (forskohlii) and Marrubium vulgare (white horehound).
References:
1.  Zerbe, P., Hamberger, B., Yuen, M.M., Chiang, A., Sandhu, H.K., Madilao, L.L., Nguyen, A., Hamberger, B., Bach, S.S. and Bohlmann, J. Gene discovery of modular diterpene metabolism in nonmodel systems. Plant Physiol. 162 (2013) 1073–1091. [PMID: 23613273]
2.  Pateraki, I., Andersen-Ranberg, J., Hamberger, B., Heskes, A.M., Martens, H.J., Zerbe, P., Bach, S.S., Moller, B.L., Bohlmann, J. and Hamberger, B. Manoyl oxide (13R), the biosynthetic precursor of forskolin, is synthesized in specialized root cork cells in Coleus forskohlii. Plant Physiol. 164 (2014) 1222–1236. [PMID: 24481136]
3.  Zerbe, P., Chiang, A., Dullat, H., O'Neil-Johnson, M., Starks, C., Hamberger, B. and Bohlmann, J. Diterpene synthases of the biosynthetic system of medicinally active diterpenoids in Marrubium vulgare. Plant J. 79 (2014) 914–927. [PMID: 24990389]
[EC 4.2.3.190 created 2017]