Reaction: phytyl diphosphate + 2-carboxy-1,4-naphthoquinone = demethylphylloquinone + diphosphate + CO2
For diagram of reaction click here.
Glossary: 2-carboxy-1,4-naphthoquinone = 1,4-dioxo-2-naphthoic acid
Other name(s): menA (gene name); ABC4 (gene name); 1,4-dioxo-2-naphthoate phytyltransferase; 1,4-diketo-2-naphthoate phytyltransferase
Systematic name: phytyl-diphosphate:2-carboxy-1,4-naphthoquinone phytyltransferase
Comments: This enzyme, found in plants and cyanobacteria, catalyses a step in the synthesis of phylloquinone (vitamin K1), an electron carrier associated with photosystem I. The enzyme catalyses the transfer of the phytyl chain synthesized by EC 220.127.116.11, geranylgeranyl diphosphate reductase, to 2-carboxy-1,4-naphthoquinone.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
1. Johnson, T.W., Shen, G., Zybailov, B., Kolling, D., Reategui, R., Beauparlant, S., Vassiliev, I.R., Bryant, D.A., Jones, A.D., Golbeck, J.H. and Chitnis, P.R. Recruitment of a foreign quinone into the A(1) site of photosystem I. I. Genetic and physiological characterization of phylloquinone biosynthetic pathway mutants in Synechocystis sp. PCC 6803. J. Biol. Chem. 275 (2000) 8523-8530. [PMID: 10722690]
2. Shimada, H., Ohno, R., Shibata, M., Ikegami, I., Onai, K., Ohto, M.A. and Takamiya, K. Inactivation and deficiency of core proteins of photosystems I and II caused by genetical phylloquinone and plastoquinone deficiency but retained lamellar structure in a T-DNA mutant of Arabidopsis. Plant J. 41 (2005) 627-637. [PMID: 15686525]