[1]THCA synthase, a flavoprotein, uses a flavin adenine dinucleotide (FAD) cofactor to catalyze the oxidative cyclization of the monoterpene moiety of cannabigerolic acid (CBGA).

A hydride is transferred from CBGA to reduce FAD, concerted by deprotonation of a hydroxyl group by a tyrosine residue.

[8] Non-enzymatic decarboxylation of THCA during storage or smoking forms THC, the principal psychoactive component of cannabis.

[10] THC and other cannabinoids are well-known to reduce nausea and vomiting and stimulate hunger, particularly in patients undergoing cancer chemotherapy.

[12] Demand is high for pharmaceutical grade THC and other cannabinoids due to interest in their potential therapeutic use, but is stymied by legal regulations of C. sativa cultivation in many countries.

[13] Direct chemical synthesis of THC is difficult due to high costs and low yields.

Production of THCA on a milligram scale has been demonstrated in Pichia pastoris yeast cells in two independent studies.