12-Lipoxygenase from rat basophilic leukemia cells, an oxygenase with leukotriene A4-synthase activity.
Rat basophilic leukemia cells exhibit 12-lipoxygenase activity only upon cell disruption. 12-Lipoxygenase may also possess 15-lipoxygenase activity, as is indicated by the formation of low amounts of 15(S)-HETE, in addition to the predominant product 12(S)-HETE, upon incubation of partially purified 12-lipoxygenase with arachidonic acid. With 5(S)-HPETE as substrate not only 5(S), 12(S)-diHETE and 5(S), 15(S)-diHETE are formed, but also LTA4, as was indicated by the presence of LTA4-derived LTB4-isomers. 12-Lipoxygenase from rat basophilic leukemia cells has many features in common with 12-lipoxygenase from bovine leukocytes. As was suggested for the latter enzyme, 12-lipoxygenase from rat basophilic leukemia cells may represent the remaining LTA4-synthase activity of 5-lipoxygenase, of which the 5-dioxygenase activity has disappeared upon cell disruption. Such a possible shift from 5-lipoxygenase activity to 12-lipoxygenase activity could not simply be induced by interaction of cytosolic 5-lipoxygenase with a membrane fraction after cell disruption, but may involve release of membrane-associated 5-lipoxygenase upon disruption of activated rat basophilic leukemia cells.
van der Donk
E M
EM
Bijvoet Center for Biomolecular Research, Department of Bio-Organic Chemistry, Utrecht University, Netherlands.
Vervaart
J M
JM
Verhagen
J
J
Veldink
G A
GA
Vliegenthart
J F
JF
D000818:Animals; D001092:Arachidonate 12-Lipoxygenase / Q000302:isolation & purification / Q000378:metabolism*; D001094:Arachidonate 5-Lipoxygenase / Q000302:isolation & purification / Q000378:metabolism*; D002458:Cell Fractionation; D002851:Chromatography, High Pressure Liquid; D003600:Cytosol / Q000201:enzymology; D006893:Hydroxyeicosatetraenoic Acids / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D015471:Leukemia, Basophilic, Acute / Q000201:enzymology*; D051381:Rats; D014407:Tumor Cells, Cultured
D006893:Hydroxyeicosatetraenoic Acids; C022022:5-hydroxy-6,8,11,14-eicosatetraenoic acid; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid; D001092:Arachidonate 12-Lipoxygenase; D001094:Arachidonate 5-Lipoxygenase