Arachidonic acid formed by peroxisomal beta-oxidation of 7,10,13,16-docosatetraenoic acid is esterified into 1-acyl-sn-glycero-3-phosphocholine by microsomes.
Peroxisomal beta-oxidation of linoleic acid and arachidonic acid was depressed when 1-palmitoyl-sn-glycero-3-phosphocholine and microsomes were included in incubations. This reduction was due to the esterification of the substrate into the acceptor by microsomal 1-acyl-sn-glycero-3- phosphocholine acyltransferase. The first cycle of the beta-oxidation of 7,10,13,16-docosatetraenoic acid was independent of 1-acyl-sn-glycero-3-phosphocholine and microsomes. However, when arachidonate was produced it was esterified rather than serving as a substrate for continued beta-oxidation. When arachidonate and linoleate were incubated with peroxisomes alone, 2-trans-4,7,10-hexadecatetraenoic acid and 2-trans-4-decadienoic acid were the respective end products of beta-oxidation. 2-Oxo-8,11-heptadecadienone, a catabolite produced from linoleate, was most likely a nonenzymatic decarboxylation product of 3-oxo-9,12-octadecadienoic acid. In addition to the termination of beta-oxidation by microsomal-peroxisomal communication, our results with linoleate and arachidonate suggest that the reaction catalyzed by 2-trans-4-cis-dienoyl-CoA reductase is the control step in double bond removal. In addition, the beta-ketothiolase step may play a regulatory role in the peroxisomal beta-oxidation of linoleate but not arachidonate or 7,10,13,16-docosatetraenoic acid.
Department of Medical Biochemistry, Ohio State University, Columbus 43210.
S P
SP
Baykousheva
D L
DL
Luthria
H
H
Sprecher
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D002250:Carbon Radioisotopes; D004883:Erucic Acids / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D013058:Mass Spectrometry; D008830:Microbodies / Q000378:metabolism*; D008862:Microsomes, Liver / Q000378:metabolism*; D010084:Oxidation-Reduction; D010713:Phosphatidylcholines / Q000096:biosynthesis*; D010743:Phospholipids / Q000096:biosynthesis*; D011865:Radioisotope Dilution Technique; D051381:Rats; D017207:Rats, Sprague-Dawley
D002250:Carbon Radioisotopes; D004883:Erucic Acids; D005231:Fatty Acids, Unsaturated; D010713:Phosphatidylcholines; D010743:Phospholipids; C011395:adrenic acid; D016718:Arachidonic Acid