IUBMB Enzyme Nomenclature


Accepted name: 4-hydroxy-3-methylbut-2-en-1-yl diphosphate reductase

Reaction: (1) 3-methylbut-3-en-1-yl diphosphate + 2 oxidized ferredoxin [iron-sulfur] cluster + H2O = (E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate + 2 reduced ferredoxin [iron-sulfur] cluster + 2 H+
(2) prenyl diphosphate + 2 oxidized ferredoxin [iron-sulfur] cluster + H2O = (E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate + 2 reduced ferredoxin [iron-sulfur] cluster + 2 H+

For diagram of reaction click here.

Glossary: isopentenyl = 3-methylbut-3-en-1-yl
prenyl = 3-methylbut-2-en-1-yl

Other name(s): isopentenyl-diphosphate:NADP+ oxidoreductase; LytB; (E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate reductase; HMBPP reductase; IspH; LytB/IspH; isopentenyl-diphosphate:ferredoxin oxidoreductase

Systematic name: 3-methylbut-3-en-1-yl-diphosphate:ferredoxin oxidoreductase

Comments: An iron-sulfur protein that contains an unusual [4Fe-4S] cluster [5,6]. This enzyme forms a system with a ferredoxin or a flavodoxin and an NAD(P)H-dependent reductase. This is the last enzyme in the non-mevalonate pathway for isoprenoid biosynthesis. This pathway, also known as the 1-deoxy-D-xylulose 5-phosphate (DOXP) or as the 2-C-methyl-D-erythritol-4-phosphate (MEP) pathway, is found in most bacteria and in plant chloroplasts. The enzyme acts in the reverse direction, producing a 5:1 mixture of 3-methylbut-3-en-1-yl diphosphate and prenyl diphosphate.

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


1. Rohdich, F., Hecht, S., Gärtner, K., Adam, P., Krieger, C., Amslinger, S., Arigoni, D., Bacher, A. and Eisenreich, W. Studies on the nonmevalonate terpene biosynthetic pathway: Metabolic role of IspH (LytB) protein. Proc. Natl. Acad. Sci. USA 99 (2002) 1158-1163. [PMID: 11818558]

2. Hintz, M., Reichenberg, A., Altincicek, B., Bahr, U., Gschwind, R.M., Kollas, A.-K., Beck, E., Wiesner, J., Eberl, M. and Jomaa, H. Identification of (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate as a major activator for human T cells in Escherichia coli, FEBS Lett. 509 (2001) 317-322. [PMID: 11741609]

3. Charon, L., Pale-Grosdemange, C. and Rohmer, M. On the reduction steps in the mevalonate independent 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway for isoprenoid biosynthesis in the bacterium Zymomonas mobilis, Tetrahedron Lett. 40 (1999) 7231-7234.

4. Röhrich, R.C., Englert, N., Troschke, K., Reichenberg, A., Hintz, M., Seeber, F., Balconi, E., Aliverti, A., Zanetti, G., Köhler, U., Pfeiffer, M., Beck, E., Jomaa, H. and Wiesner, J. Reconstitution of an apicoplast-localised electron transfer pathway involved in the isoprenoid biosynthesis of Plasmodium falciparum, FEBS Lett. 579 (2005) 6433-6438. [PMID: 16289098]

5. Wolff, M., Seemann, M., Bui, T.S.B., Frapart, Y., Tritsch, D., Garcia Estrabot, A., Rodríguez-Concepción, M., Boronat, A., Marquet, A. and Rohmer, M. Isoprenoid biosynthesis via the methylerythritol phosphate pathway: the (E)-4-hydroxy-3-methylbut-2-enyl diphosphate reductase (LytB/IspH) from Escherichia coli is a [4Fe-4S] protein. FEBS Lett. 541 (2003) 115-120. [PMID: 12706830]

6. Faus, I., Reinhard, A., Rackwitz, S., Wolny, J.A., Schlage, K., Wille, H.C., Chumakov, A., Krasutsky, S., Chaignon, P., Poulter, C.D., Seemann, M. and Schunemann, V. Isoprenoid biosynthesis in pathogenic bacteria: nuclear resonance vibrational spectroscopy provides insight into the unusual [4Fe-4S] cluster of the E. coli LytB/IspH protein. Angew. Chem. Int. Ed. Engl. 54 (2015) 12584-12587. [PMID: 26118554]

[EC created 2003 as EC, modified 2009, transferred 2016 to EC]

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