IUBMB Enzyme Nomenclature


Accepted name: homogentisate geranylgeranyltransferase

Reaction: geranylgeranyl diphosphate + homogentisate = diphosphate + 6-geranylgeranyl-2-methylbenzene-1,4-diol + CO2

For diagram of reaction click here.

Glossary: 6-geranylgeranyl-2-methylbenzene-1,4-diol = MGGBQ

Other name(s): HGGT; slr1736 (gene name)

Systematic name: geranylgeranyl-diphosphate:homogentisate geranylgeranyltransferase

Comments: Requires Mg2+ for activity. Involved in the biosynthesis of the vitamin E, tocotrienols. While the enzyme from the bacterium Synechocystis PCC 6803 has higher activity with phytyl diphosphate (EC, homogentisate phytyltransferase), the enzymes from barley, rice and wheat have only a low activity with that substrate [2].

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:


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. Cahoon, E.B., Hall, S.E., Ripp, K.G., Ganzke, T.S., Hitz, W.D. and Coughlan, S.J. Metabolic redesign of vitamin E biosynthesis in plants for tocotrienol production and increased antioxidant content. Nat. Biotechnol. 21 (2003) 1082-1087. [PMID: 12897790]

3. 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]

[EC created 2014]

Return to EC 2.5.1 home page
Return to EC 2.5 home page
Return to EC 2 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page