L-Tryptophan decarboxylase (EC 4.1.1.105) is an enzyme distinguished by the substrate L-tryptophan. This enzyme catalyzes the reaction of L-tryptophan to tryptamine and carbon dioxide. The enzymatic reaction namely takes place in the species Psilocybe cubensis, where a decarboxylase, kinase, and methyltransferase work together to synthesize psilocybin.