Related Experiment Videos
The last step in cocaine biosynthesis is catalyzed by a BAHD acyltransferase
Gregor Wolfgang Schmidt1, Jan Jirschitzka1, Tiffany Porta1
1Department of Biochemistry, Max Planck Institute for Chemical Ecology, Beutenberg Campus, D-07745 Jena, Germany (G.W.S., J.J., M.R., K.L., J.C.P.T., F.D., J.G., J.C.D.); andLife Sciences Mass Spectrometry Research Unit, School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, 1211 Geneva, Switzerland (T.P., E.V., G.H.).
Abstract:
The esterification of methylecgonine (2-carbomethoxy-3β-tropine) with benzoic acid is the final step in the biosynthetic pathway leading to the production of cocaine in Erythoxylum coca. Here we report the identification of a member of the BAHD family of plant acyltransferases as cocaine synthase. The enzyme is capable of producing both cocaine and cinnamoylcocaine via the activated benzoyl- or cinnamoyl-Coenzyme A thioesters, respectively. Cocaine synthase activity is highest in young developing leaves, especially in the palisade parenchyma and spongy mesophyll. These data correlate well with the tissue distribution pattern of cocaine as visualized with antibodies. Matrix-assisted laser-desorption ionization mass spectral imaging revealed that cocaine and cinnamoylcocaine are differently distributed on the upper versus lower leaf surfaces. Our findings provide further evidence that tropane alkaloid biosynthesis in the Erythroxylaceae occurs in the above-ground portions of the plant in contrast with the Solanaceae, in which tropane alkaloid biosynthesis occurs in the roots.