Reaction: (1) S-adenosyl-L-methionine + γ-tocopherol = S-adenosyl-L-homocysteine + α-tocopherol
(2) S-adenosyl-L-methionine + δ-tocopherol = S-adenosyl-L-homocysteine + β-tocopherol
(3) S-adenosyl-L-methionine + γ-tocotrienol = S-adenosyl-L-homocysteine + α-tocotrienol
(4) S-adenosyl-L-methionine + δ-tocotrienol = S-adenosyl-L-homocysteine + β-tocotrienol
For diagram of reaction, click here or click here
Other name(s): γ-tocopherol methyltransferase; VTE4 (gene name); S-adenosyl-L-methionine:γ-tocopherol 5-O-methyltransferase (incorrect); tocopherol O-methyltransferase (incorrect)
Systematic name: S-adenosyl-L-methionine:γ-tocopherol 5-C-methyltransferase
Comments: The enzymes from plants and photosynthetic bacteria have similar efficiency with the γ and δ isomers of tocopherols and tocotrienols.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 84788-82-9
References:
1. Camara, B. and D'Harlingue, A. Demonstration and solubilization of S-adenosylmethionine: γ-tocopherol methyltransferase from Capsicum chromoplasts. Plant Cell Rep. 4 (1985) 31-32. [PMID: 24253640]
2. Koch, M., Lemke, R., Heise, K.P. and Mock, H.P. Characterization of γ-tocopherol methyltransferases from Capsicum annuum L and Arabidopsis thaliana. Eur. J. Biochem. 270 (2003) 84-92. [PMID: 12492478]
3. Zhang, G.Y., Liu, R.R., Xu, G., Zhang, P., Li, Y., Tang, K.X., Liang, G.H. and Liu, Q.Q. Increased α-tocotrienol content in seeds of transgenic rice overexpressing Arabidopsis γ-tocopherol methyltransferase. Transgenic Res. 22 (2013) 89-99. [PMID: 22763462]