NADPH-dependent reduction of 2,6-dichlorophenol-indophenol by the phagocytic vesicles of pig polymorphonuclear leucocytes
- 15 February 1983
- journal article
- research article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 210 (2), 577-581
- https://doi.org/10.1042/bj2100577
Abstract
NADPH-dependent 2,6-dichlorophenol-indophenol (DCIP) reductase activity in the homogenate of phagocytosing pig polymorphonuclear leukocytes was twice that of the resting cells and the activity in the phagocytic vesicles corresponded to the activity increment due to phagocytosis. The apparent Km value of the reductase activity in the vesicles for NADPH was 30 .mu.M, which is similar to that of the NADPH-dependent superoxide (O2-) formation. Increasing the DCIP reductase activity by increasing the DCIP concentration caused a decrease in the O2--forming activity, the NADPH oxidation rate being constant and independent of the dye concentration. p-Chloromercuribenzoate and cetyltrimethylammonium bromide at low concentrations inhibited the O2--forming activity of the vesicles without inhibiting the DCIP reductase. Quinacrine inhibited both O2- formation and DCIP reduction. The DCIP reductase activity could be extracted with a mixture of deoxycholate and Tween-20, which extracts the O2--forming activity. The reductase activity in the extract was enhanced 2-fold by the addition of FAD, and its apparent Km was 0.085 .mu.M. The NADPH-dependent DCIP reductase activity of the phagocytic vesicles apparently is catalyzed by a flavin-containing component of the O2--forming system.This publication has 18 references indexed in Scilit:
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