Cannabidiolic acid synthase

Cannabidiolic acid synthase (EC 1.21.3.8, CBDA synthase) is an enzyme with systematic name cannabigerolate:oxygen oxidoreductase (cyclizing, cannabidiolate-forming).[1][2] It is an oxidoreductase found in Cannabis sativa that catalyses the formation of cannabidiolate, a carboxylated precursor of cannabidiol.[2]

Cannabidiolic acid synthase
Identifiers
EC number1.21.3.8
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum

Enzyme structure

Cannabidiolic acid synthase consists of a single protein with a molecular mass of 74 kDa.[1] Its amino acid sequence is partly (40-50%) homologous to several other oxidoreductases,[2] such as berberine bridge enzyme in Eschscholzia californica[3] and Nectarin V in Nicotiana langsdorffii X N. sanderae.[4]

CBDA synthase has four binding sites; two for FAD and two for the substrate.[5]

Enzyme function

Cannabidiolic acid synthase catalyses the production of cannabidiolate predominantly from cannabigerolate by stereospecific oxidative cyclization of the geranyl group of cannabigerolic acid[2] according to the following chemical reaction:

cannabigerolate + O2 → cannabidiolate + H2O2

Cannabinerolate can also be used as a substrate, but with lower efficiency (KM=0.137 mM) than cannabigerolate (KM=0.206 mM). It covalently binds FAD, and does require coenzymes & molecular oxygen for the oxidocyclization reaction.[1]

The optimum pH for CBDA synthase is 5.0. [2]

References
  1. Taura F, Morimoto S, Shoyama Y (July 1996). "Purification and characterization of cannabidiolic-acid synthase from Cannabis sativa L.. Biochemical analysis of a novel enzyme that catalyzes the oxidocyclization of cannabigerolic acid to cannabidiolic acid". The Journal of Biological Chemistry. 271 (29): 17411–6. doi:10.1074/jbc.271.29.17411. PMID 8663284.
  2. Taura F, Sirikantaramas S, Shoyama Y, Yoshikai K, Shoyama Y, Morimoto S (June 2007). "Cannabidiolic-acid synthase, the chemotype-determining enzyme in the fiber-type Cannabis sativa". FEBS Letters. 581 (16): 2929–34. doi:10.1016/j.febslet.2007.05.043. PMID 17544411.
  3. Kutchan TM, Dittrich H (October 1995). "Characterization and mechanism of the berberine bridge enzyme, a covalently flavinylated oxidase of benzophenanthridine alkaloid biosynthesis in plants". The Journal of Biological Chemistry. 270 (41): 24475–81. doi:10.1074/jbc.270.41.24475. PMID 7592663.
  4. Carter CJ, Thornburg RW (January 2004). "Tobacco nectarin V is a flavin-containing berberine bridge enzyme-like protein with glucose oxidase activity". Plant Physiology. 134 (1): 460–9. doi:10.1104/pp.103.027482. PMC 316325. PMID 14730073.
  5. "CBDAS - Cannabidiolic acid synthase precursor - Cannabis sativa (Hemp) - CBDAS gene & protein". UniProt. Retrieved 26 February 2016.
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