title: Properties of lysophosphatidylcholine acyltransferase from Brassica napus cultures.
abstract: Acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT; EC 2.3.1.23) catalyzes the acyl-CoA-dependent acylation of lysophosphatidylcholine (LPC) to produce PC and CoA. LPCAT activity may affect the incorporation of fatty acyl moieties at the sn-2 position of PC where PUFA are formed and may indirectly influence seed TAG composition. LPCAT activity in microsomes prepared from microspore-derived cell suspension cultures of oilseed rape (Brassica napus L. cv Jet Neuf) was assayed using [1-14C]acyl-CoA as the fatty acyl donor. LPCAT activity was optimal at neutral pH and 35 degrees C, and was inhibited by 50% at a BSA concentration of 3 mg mL(-1). At acyl-CoA concentrations above 20 microM, LPCAT activity was more specific for oleoyl (18:1)-CoA than stearoyl (18:0)- and palmitoyl (16:0)-CoA. Lauroyl (12:0)-CoA, however, was not an effective acyl donor. LPC species containing 12:0, 16:0, 18:0, or 18:1 as the fatty acyl moiety all served as effective acyl acceptors for LPCAT, although 12:0-LPC was somewhat less effective as a substrate at lower concentrations. The failure of LPCAT to catalyze the incorporation of a 12:0 moiety from acyl-CoA into PC is consistent with the tendency of acyltransferases to discriminate against incorporation of this fatty acyl moiety at the sn-2 position of TAG from the seed oil of transgenic B. napus expressing a medium-chain thioesterase.
authors.affiliation: Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, T1K 3M4 Canada.
authors.forename: Tara L
authors.initials: TL
authors.lastname: Furukawa-Stoffer
authors.forename: Riley M
authors.initials: RM
authors.lastname: Boyle
authors.forename: Amber L
authors.initials: AL
authors.lastname: Thomson
authors.forename: Magdalena A
authors.initials: MA
authors.lastname: Sarna
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Weselake
mesh_terms: D008243:1-Acylglycerophosphocholine O-Acyltransferase / Q000378:metabolism*; D000214:Acyl Coenzyme A / Q000378:metabolism; D029688:Brassica napus / Q000201:enzymology*; D002250:Carbon Radioisotopes; D002478:Cells, Cultured; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008244:Lysophosphatidylcholines / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D013997:Time Factors
chemical_list: D000214:Acyl Coenzyme A; D002250:Carbon Radioisotopes; D005231:Fatty Acids, Unsaturated; D008244:Lysophosphatidylcholines; D008243:1-Acylglycerophosphocholine O-Acyltransferase