Topology of cytochrome b558 in neutrophil membrane analyzed by anti-peptide antibodies and proteolysis.

摘要: Cytochrome b558 is an important constituent of the superoxide-generating system in neutrophils and B lymphocytes. In this paper, topology cytochrome human neutrophil membrane was studied using antibodies raised rabbits against synthetic peptides corresponding to various regions large small subunits cytochrome. The recognized immunoblots situ. An antibody residues 150-172 subunit (anti-L123) bound intact neutrophils, indicating that region exposed outside cells. contrast, any carboxyl-terminal (anti-LC anti-SC, respectively) or amino-terminal (anti-SN), only after cells were made permeable by freezing thawing. close carboxyl terminus digested extracellularly added papain and, as a result, 18-kDa fragment detected. Thus cytoplasmic and/or buried membrane, around 369-398 on cell surface. contrast subunits, resistant proteinases tested, although Triton-solubilized preparation digestible with papain. These results indicate transmembrane protein at least two surface both termini are side.