IUBMB Enzyme Nomenclature


Accepted name: cycloeucalenol cycloisomerase

Reaction: cycloeucalenol = obtusifoliol

For diagram click here.

Other name(s): cycloeucalenol—obtusifoliol isomerase; cycloeucalenol lyase (cyclopropane-decyclizing)

Systematic name: cycloeucalenol lyase (cyclopropane-ring opening)

Comments: Opens the cyclopropane ring of a number of related 4α-methyl-9β-19-cyclosterols, but not those with a 4β-methyl group, with formation of an 8(9) double bond. Involved in the synthesis of plant sterols.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 60496-19-7


1. Heintz, R. and Benveniste, P. Plant sterol metabolism. Enzymatic cleavage of the 9β,19β-cyclopropane ring of cyclopropyl sterols in bramble tissue cultures. J. Biol. Chem. 249 (1974) 4267-4274. [PMID: 4369016]

2. Rahier, A., Schmitt, P. and Benveniste, P. 7-oxo-24ξ(28)-dihydrocycloeucalenol, a potent inhibitor of plant sterol biosynthesis. Phytochemistry 21 (1982) 1969-1974.

[EC created 1986]

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