Cannabidiolic acid synthase

See also: Tetrahydrocannabinolic 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 no.	1.21.3.8
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Search PMC articles PubMed articles NCBI proteins

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 (K_M=0.137 mM) than cannabigerolate (K_M=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]