抄録
The superoxide-producing NADPH oxidase consists of membrane-associated cytochrome b558 (gp 91-phox and p 22-phox) and cytosolic components. We purified a 260 kDa cytosolic complex which was essential for the activation of NADPH oxidase. This complex was composed of p 47-phox, p 67-phox and a novel p 40-phox. We examined the translocation of p 40-phox in a cell-free system using membrane and purified p 47-phox/p 67-phox/p 40-phox complex. p 40-phox was translocated to the membrane by arachidonic acid in a dose-dependent manner. The translocation pattern of p 40-phux was similar to those of p 47-phox and p 67-phox. Immunoprecipitation assay revealed that p 40-phox was dissociated from p 47-phox and p 67-phox during activation. Furthermore, a synthetic peptide corresponding to carboxyl-terminus of p 40-phox inhibited the activation of NADPH oxidase and translocation of p 40-phox, p 47-phox and p 67-phox. These observations suggest that p 40-phox may play a role in the activation of NADPH oxidase through interacting with p 47-phox and p 67-phox via its carboxyl-terminus.
