4-hydroxy-3-methylbut-2-en-1-yl diphosphate synthase

(E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate + H₂O + protein-disulfide $\rightleftharpoons$ 2-C-methyl-D-erythritol 2,4-cyclodiphosphate + protein-dithiol

The 3 substrates of this enzyme are (E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate (HMB-PP), H₂O, and protein disulfide, whereas its two products are 2-C-methyl-D-erythritol 2,4-cyclodiphosphate and protein dithiol.

This enzyme belongs to the family of oxidoreductases, specifically those acting on CH or CH2 group with a disulfide as acceptor. The systematic name of this enzyme class is (E)-4-hydroxy-3-methylbut-2-en-1-yl-diphosphate:protein-disulfide oxidoreductase (hydrating). This enzyme participates in biosynthesis of steroids.

References

D, Rohdich F; Eisenreich, W; Adam, P; Amslinger, S; Kis, K; Bacher, A; Arigoni, D; Rohdich, F (2001). "Studies on the nonmevalonate pathway to terpenes: the role of the GcpE (IspG) protein". Proc. Natl. Acad. Sci. U. S. A. 98 (26): 14837–42. doi:10.1073/pnas.201399298. PMC 64945. PMID 11752431. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=64945.

Metabolism - non-mevalonate pathway enzymes

DXP synthase - DXP reductoisomerase - 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase - 2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase - 4-(cytidine 5'-diphospho)-2-C-methyl-D-erythritol kinase - 4-hydroxy-3-methylbut-2-en-1-yl diphosphate synthase - 4-hydroxy-3-methylbut-2-enyl diphosphate reductase