Reaction: phytyl diphosphate + homogentisate = diphosphate + 2-methyl-6-phytylbenzene-1,4-diol + CO2
For diagram of reaction click here.
Glossary: 2-methyl-6-phytylbenzene-1,4-diol = MPBQ
Other name(s): HPT; VTE2 (gene name)
Systematic name: phytyl-diphosphate:homogentisate phytyltransferase
Comments: Requires Mg2+ for activity [3]. Involved in the biosynthesis of the vitamin E tocopherols. While the enzyme from the cyanobacterium Synechocystis PCC 6803 has an appreciable activity with geranylgeranyl diphosphate (EC 2.5.1.116, homogentisate geranylgeranyltransferase), the enzyme from the plant Arabidopsis thaliana has only a low activity with that substrate [1,3,4].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Collakova, E. and DellaPenna, D. Isolation and functional analysis of homogentisate phytyltransferase from Synechocystis sp. PCC 6803 and Arabidopsis. Plant Physiol. 127 (2001) 1113-1124. [PMID: 11706191]
2. Savidge, B., Weiss, J.D., Wong, Y.H., Lassner, M.W., Mitsky, T.A., Shewmaker, C.K., Post-Beittenmiller, D. and Valentin, H.E. Isolation and characterization of homogentisate phytyltransferase genes from Synechocystis sp. PCC 6803 and Arabidopsis. Plant Physiol. 129 (2002) 321-332. [PMID: 12011362]
3. Sadre, R., Gruber, J. and Frentzen, M. Characterization of homogentisate prenyltransferases involved in plastoquinone-9 and tocochromanol biosynthesis. FEBS Lett 580 (2006) 5357-5362. [PMID: 16989822]
4. Yang, W., Cahoon, R.E., Hunter, S.C., Zhang, C., Han, J., Borgschulte, T. and Cahoon, E.B. Vitamin E biosynthesis: functional characterization of the monocot homogentisate geranylgeranyl transferase. Plant J. 65 (2011) 206-217. [PMID: 21223386]