Any feedback?
Please rate this page
(ecexplorer.php)
(0/150)

BRENDA support

EC Explorer

EC 2.5.1.21 Details
EC number
2.5.1.21
Accepted name
squalene synthase
Reaction
2 (2E,6E)-farnesyl diphosphate + NAD(P)H + H+ = squalene + 2 diphosphate + NAD(P)+ (overall reaction);;(1a) 2 (2E,6E)-farnesyl diphosphate = diphosphate + presqualene diphosphate;;(1b) presqualene diphosphate + NAD(P)H + H+ = squalene + diphosphate + NAD(P)+
Other name(s)
farnesyltransferase, presqualene-diphosphate synthase, presqualene synthase, squalene synthetase, farnesyl-diphosphate farnesyltransferase, SQS
Systematic name
(2E,6E)-farnesyl-diphosphate:(2E,6E)-farnesyl-diphosphate farnesyltransferase
CAS registry number
9077-14-9
Comment
This microsomal enzyme catalyses the first committed step in the biosynthesis of sterols. The enzyme from yeast requires either Mg2+ or Mn2+ for activity. In the absence of NAD(P)H, presqualene diphosphate (PSPP) is accumulated. When NAD(P)H is present, presqualene diphosphate does not dissociate from the enzyme during the synthesis of squalene from farnesyl diphosphate (FPP) [8]. High concentrations of FPP inhibit the production of squalene but not of PSPP [8].
History
created 1976, modified 2005, modified 2012
EC Tree
2.5.1.12 created 1972, deleted 1976
2.5.1.13 created 1972, deleted 1976
2.5.1.14 created 1972, deleted 1976
2.5.1.37 created 1989, deleted 2004
2.5.1.40 created 1992, deleted 1999