NAD+-dependent conversion of 20-OH-LTB4 to 20-COOH-LTB4 by a cell-free system of human polymorphonuclear leukocytes.

Human polymorphonuclear leukocytes, but not mononuclear leukocytes, platelets, or erythrocytes, oxidized 20-hydroxy-leukotriene B4 (20-OH-LTB4) to 20-carboxy-LTB4 (20-COOH-LTB4). 20-OH-LTB4 was quantitatively converted to 20-COOH-LTB4 by the sonicate of polymorphonuclear leukocytes in the presence of NAD+, with an optimal pH of about 7.9. NADP+ could not replace NAD+. The conversion was not inhibited by 2 mM pyrazole, a potent inhibitor of alcohol dehydrogenase. When LTB4 was incubated with the sonicate in the presence of NADPH and NAD+, 20-OH-LTB4 and 20-COOH-LTB4 appeared concomitantly with the disappearance of LTB4.