Cloning and characterization of a γ-tocopherol methyltransferase from Chinese cabbage

Abstract

α-Tocopherol, with antioxidant properties, is synthesized by photosynthetic organisms and play important roles in human and animal nutrition. The final step of the α-tocopherol biosynthetic pathway is catalyzed by γ-tocopherol methyltransferase (γ-TMT). In the major oilseed crops, γ-tocopherol, the biosynthetic precursor of α-tocopherol, is the predominant form. The full-length cDNA of γ-TMT was obtained from Chinese cabbage (Brassica. rapa, Pekinensis Group), named BoTMT, by reverse transcription polymerase chain reaction (RT-PCR). Sequence analysis indicates that, BoTMT gene consisted of the open reading frame of 1041 nucleotides encoding a protein of 39 kD polypeptide. A BoTMT whole cell system was developed for the production of α-tocopherol through the expression of BoTMT in Escherichia coli BL21 (DE3) strain.

Keywords: γ-Tocopherol methyltransferase, Chinese cabbage, Perilla frustescens, tocopherol, high performance liquid chromatography (HPLC)