Plant Physiol, May 2000, Vol. 123, pp. 287-296

Metabolism of Methanol in Plant Cells. Carbon-13 Nuclear Magnetic Resonance Studies

Laboratoire de Résonance Magnétique en Biologie Métabolique, Département de Biologie Moléculaire et Structurale, CEA-38054, Grenoble cedex 9, France (E.G.); Laboratoire de Physiologie Cellulaire Végétale, Unité de Recherche Associée 576 Commissariat à l'Energie Atomique/Centre National de la Recherche Scientifique/Université Joseph Fourier, CEA-38054, Grenoble cedex 9, France (S.A., R.B., F.R., R.D.); Farlow Herbarium, Harvard University, Cambridge, Massachusetts 02138 (A.R.N.); and Scripps Institution of Oceanography, University of California, San Diego, California 92093-0202 (A.A.B.)

Using ¹³C-NMR, we demonstrate that [¹³C]methanol readily entered sycamore (Acer pseudoplatanus L.) cells to be slowly metabolized to [3-¹³C]serine, [¹³CH₃]methionine, and [¹³CH₃]phosphatidylcholine. We conclude that the assimilation of [¹³C]methanol occurs through the formation of ¹³CH₃H₄Pte-glutamate (Glu)_n and S-adenosyl-methionine, because feeding plant cells with [3-¹³CH₃]serine, the direct precursor of ¹³CH₂H₄Pte-Glu_n, can perfectly mimic [¹³CH₃]methanol for folate-mediated single-carbon metabolism. On the other hand, the metabolism of [¹³C]methanol in plant cells revealed assimilation of label into a new cellular product that was identified as [¹³CH₃]methyl--D-glucopyranoside. The de novo synthesis of methyl--D-glucopyranoside induced by methanol did not require the formation of ¹³CH₃H₄Pte-Glu_n and was very likely catalyzed by a "transglycosylation" process.