NUCLEOSIDE-TRIPHOSPHATE BINDING OF THE 2 CYTOSOLIC COMPONENTS OF THE RESPIRATORY BURST OXIDASE SYSTEM - EVIDENCE FOR ITS INHIBITION BY THE 2',3'-DIALDEHYDE DERIVATIVE OF NADPH AND DESENSITIZATION IN THEIR TRANSLOCATED STATES

Citation
H. Mizunari et al., NUCLEOSIDE-TRIPHOSPHATE BINDING OF THE 2 CYTOSOLIC COMPONENTS OF THE RESPIRATORY BURST OXIDASE SYSTEM - EVIDENCE FOR ITS INHIBITION BY THE 2',3'-DIALDEHYDE DERIVATIVE OF NADPH AND DESENSITIZATION IN THEIR TRANSLOCATED STATES, Biochimica et biophysica acta, 1220(1), 1993, pp. 21-30
Citations number
35
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biophysics,Biology
ISSN journal
0006-3002
Volume
1220
Issue
1
Year of publication
1993
Pages
21 - 30
Database
ISI
SICI code
0006-3002(1993)1220:1<21:NBOT2C>2.0.ZU;2-4
Abstract
Affinity labeling of the two cytosolic components of the respiratory b urst oxidase system, p49-phox and p63-phox, from resting porcine neutr ophils was carried out with [P-32]NADPH dialdehyde (oNADPH), [P-32]oGT P and [P-32]oATP. p49-phox and p63-phox showed 10-times higher affinit ies for both oGTP and oATP than for oNADPH, suggesting that they are n ucleoside triphosphate (NTP)-binding proteins, rather than the NADPH-b inding site of the oxidase. In addition, oNADPH markedly inhibited the affinity labeling of p49-phox with [P-32]oGTP and [P-32]oATP, well re flecting its inhibitory effect on the oxidase activity in the cell-fre e system, which was previously reported to propose the NADPH-binding s ite in a cytosolic component. Stimulation of porcine neutrophils with either myristic acid or phorbol myristate acetate resulted in great en hancement of the oxidase activity, and in considerable translocation o f p49-phox and p63-phox. Nevertheless, the affinity labeling of the st imulated cell membranes in both cases revealed no labeled bands corres ponding to molecular masses of 49 kDa and 63 kDa. p49-phox derived fro m the stimulated membranes had lost its [P-32]oGTP binding ability in contrast with that from resting cytosol, suggesting that the NTP-bindi ng sites of the two cytosolic components may be desensitized on NTP bi nding in their translocated states.