Stereoselective hydrogen abstraction in leukotriene A4 synthesis by purified 5-lipoxygenase of porcine leukocytes.
Arachidonate 5-lipoxygenase purified from porcine leukocytes transformed arachidonic acid to 5-hydroperoxy-6,8,11,14-eicosatetraenoic acid. By the leukotriene A synthase activity of the same enzyme the product was further metabolized to leukotriene A4 (actually detected as 6-trans-leukotriene B4, 12-epi-6-trans-leukotriene B4, and 5,6-dihydroxy-7,9,11,14-eicosatetraenoic acids). The enzyme was incubated with [10-DR-3H]- or [10-LS-3H]-labeled arachidonic acid, and 6-trans-LTB4 and its 12-epimer were analyzed. More than 90% of 10-DR-hydrogen was lost while about 100% of 10-LS-hydrogen was retained, indicating a stereospecific hydrogen elimination from C-10 during the formation of leukotriene A4.
D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000097:blood* / Q000302:isolation & purification; D001091:Arachidonate Lipoxygenases / Q000097:blood*; D001095:Arachidonic Acids / Q000096:biosynthesis* / Q000097:blood; D002250:Carbon Radioisotopes; D002851:Chromatography, High Pressure Liquid; D007962:Leukocytes / Q000201:enzymology*; D017572:Leukotriene A4; D013552:Swine; D014316:Tritium
D001095:Arachidonic Acids; D002250:Carbon Radioisotopes; D017572:Leukotriene A4; D014316:Tritium; D001091:Arachidonate Lipoxygenases; D001094:Arachidonate 5-Lipoxygenase