Subcellular localization of the superoxide-forming enzyme in human neutrophils.
AUTOR(ES)
Dewald, B
RESUMO
The subcellular distribution of the superoxide (O2-)-forming enzyme in human neutrophils was investigated. Cells were activated by phorbolmyristate acetate or by opsonized zymosan, and were then fractionated by zonal-rate sedimentation at two different speeds. At high speed, the specific granules were resolved from the azurophils and the membrane fraction, while at low speed, the azurophil granules could be separated from fast-sedimenting particle aggregates. Under both conditions, the major portion of the O-2--forming activity (60--70% of the total) was found to be associated with the membrane fraction which was characterized by the presence of alkaline phosphatase, alkaline phosphodiesterase I, and acid aryl phosphatase. No significant O-2--forming activity was found in either specific or azurophil granules. Some activity was present in the fastest sedimenting fractions which, as shown by electron microscopy, were heterogeneous and contained aggregated material which included membrane fragments. These fractionation results provide strong additional support for the current view that the activable O-2--forming system is localized in the plasma membrane of human neutrophils.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=371913Documentos Relacionados
- Monoclonal antibodies to a particulate superoxide-forming system stimulate a respiratory burst in intact guinea pig neutrophils.
- The particulate superoxide-forming system from human neutrophils. Properties of the system and further evidence supporting its participation in the respiratory burst.
- Subcellular localization and dynamics of Mac-1 (alpha m beta 2) in human neutrophils.
- Subcellular distribution of Ca2+ pumping sites in human neutrophils.
- Intracellular pH modulates the generation of superoxide radicals by human neutrophils.