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NADP efficiently inhibits endogenous but not pertussis toxin-catalyzed covalent modification of membrane proteins incubated with NAD

Item Type:Article
Title:NADP efficiently inhibits endogenous but not pertussis toxin-catalyzed covalent modification of membrane proteins incubated with NAD
Creators Name:Rosenthal, W. and Binder, T. and Schultz, G.
Abstract:Incubation of membranes of human erythrocytes and platelets but not of human neutrophils with [32P]NAD leads to covalent modification of various membrane proteins and of added albumin. In membranes of all three cell types, pertussis toxin (PT), in the presence of NAD, specifically labelled a 40 kDa peptide, i.e. the alpha-subunit of a guanine nucleotide-binding protein. This effect of PT was slightly reduced by NADP, whereas modification of other membrane proteins and of albumin was largely suppressed, independent of whether PT was present or not. Labelling of cytosolic proteins in the presence of NAD was marginal; only in neutrophil cytosol, PT modified a 40 kDa peptide. Membranes of erythrocytes and platelets exhibited NAD-degrading activity, which was inhibited by NADP. The data suggest a high substrate specificity of PT for NAD. Inhibition of endogenous enzymes by NADP may prove useful for the evaluation of PT substrates.
Keywords:Pertussis Toxin, ADP-Ribosylation, Guanine Nucleotide-Binding Protein, NADP
Source:FEBS Letters
ISSN:0014-5793
Publisher:Elsevier (The Netherlands)
Volume:211
Number:2
Page Range:137-143
Date:26 January 1987
Official Publication:https://doi.org/10.1016/0014-5793(87)81424-2
PubMed:View item in PubMed

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