Molecular properties of the oleoyl-phosphatidylcholine desaturase from Arachis hypogaea L.
Deficiencies in the activity of the microsomal oleoyl phosphatidylcholine (oleoyl-PC) desaturase from peanuts are the basis of the high oleate oil. Mutation of aspartate-150 to asparagine and the attendant decrease in activity, together with the loss in expression of the higher activity transcript, was the molecular basis of the high oleate trait. The ability of oleoyl-PC desaturase to desaturate palmitoleate, oleate and 10(Z) nonadecenoate to methylene-interrupted products was not consistent with description of this activity as a Delta(12) or omega-6 desaturase. Electrospray MS was used to examine the intact phospholipid products of desaturation by the oleoyl-PC desaturase. PC and phosphatidylinositol containing unsaturated moieties could be desaturated. The enzyme can act on either sn-1 or sn-2 moieties. Phosphatidylethanolamine was a poor substrate.
Powell
G L
GL
Department of Biological Sciences, Clemson University, Clemson, SC 29634-0326, USA. glpwl@clemson.edu
Jung
S
S
Bruner
A C
AC
Swartzbeck
J L
JL
Abbott
A G
AG
D019943:Amino Acid Substitution; D010367:Arachis / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D044943:Fatty Acid Desaturases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D044925:Oxidoreductases Acting on CH-CH Group Donors; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D021241:Spectrometry, Mass, Electrospray Ionization; D014158:Transcription, Genetic
D005227:Fatty Acids; D011994:Recombinant Proteins; D044943:Fatty Acid Desaturases; C021904:Phosphatidylcholine desaturase; D044925:Oxidoreductases Acting on CH-CH Group Donors