IUBMB Enzyme Nomenclature


Accepted name: hydroxysqualene dehydroxylase

Reaction: squalene + FAD + H2O = hydroxysqualene + FADH2

Glossary: hydroxysqualene = (6E,10E,12R,14E,18E)-2,6,10,15,19,23-hexamethyltetracosa-2,6,10,14,18,22-hexaen-12-ol

Other name(s): hpnE (gene name)

Systematic name: squalene:FAD oxidoreductase (hydroxylating)

Comments: This enzyme, isolated from the bacteria Rhodopseudomonas palustris and Zymomonas mobilis, participates, along with EC, presqualene diphosphate synthase, and EC, hydroxysqualene synthase, in the conversion of all-trans-farnesyl diphosphate to squalene. Eukaryotes achieve the same goal in a single step, catalysed by EC, squalene synthase.

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


1. Pan, J.J., Solbiati, J.O., Ramamoorthy, G., Hillerich, B.S., Seidel, R.D., Cronan, J.E., Almo, S.C. and Poulter, C.D. Biosynthesis of squalene from farnesyl diphosphate in bacteria: three steps catalyzed by three enzymes. ACS Cent Sci 1 (2015) 77-82. [PMID: 26258173]

[EC created 2016]

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