High impact information on C01054

• Squalene epoxidase, a membrane-associated enzyme that converts squalene to squalene 2,3-oxide, plays an important role in the maintenance of cholesterol homeostasis [1].
• The ERG7 gene encoding oxidosqualene-lanosterol cyclase [(S)-2,3-epoxysqualene mutase (cyclizing, lanosterol forming), EC 5.4.99.7] from Saccharomyces cerevisiae has been cloned by genetic complementation of a cyclase-deficient erg7 strain [2].
• We conclude that 1) cholesterol biosynthesis may be topographically heterogeneous and 2) newly synthesized squalene 2,3-oxide resides in a buoyant membrane fraction distinct from markers for the major organelles [3].
• SPF also significantly enhances the formation of lanosterol from squalene-2,3-oxide already bound to microsomes [4].
• Hep G2 cells were incubated under conditions known to influence the HMG-CoA (3-hydroxy-3-methylglutaryl-CoA) reductase activity, e.g. in the presence of compactin (a competitive inhibitor of HMG-CoA reductase itself) and U18666A (a squalene-2,3-epoxide cyclase inhibitor) [5].

Biological context of C01054

• The ability of some azasqualene derivatives to inhibit yeast cell growth was compared with their inhibition activity on squalene-2,3-oxide cyclase (EC 5.4.99.7) both in living cells and in microsome preparations [6].

Anatomical context of C01054

• N-[(1,5,9)-trimethyldecyl]-4 alpha,10-dimethyl-8-aza-trans-decal-3 beta-ol (MDL 28,815) has been shown to block cholesterol biosynthesis in 3T3 fibroblasts and it causes cellular accumulation of squalene 2,3-epoxide and squalene 2,3:23,24-diepoxide (squalene epoxides), which suggests that it inhibits 2,3-oxidosqualene cyclase [7].

References