NADP efficiently inhibits endogenous but not pertussis toxin‐catalyzed co valent modification of membrane proteins incubated with NAD

FEBS Letters

Rosenthal, W.¹  Schultz, G.¹  Binder, T.¹ 

[1] Pharmakologisches Institut der Freien Universität Berlin, Thielallee 69-73, D-1000 Berlin 33, Germany

关键词: Pertussis toxin;    ADP-ribosylation;    Guanine nucleotide-binding protein;    NADP;    PMNs;    polymorphonuclear neutrophils;    RBCs;    red blood cells;    PT;    pertussis toxin;    CT;    cholera toxin;    N-protein;    guanine nucleotide-binding protein;    BSA;    bovine serum albumin (Cohn fraction V);    SDS-PAGE;    SDS-polyacrylamide gel electrophoresis;    TLC;    thin-layer chromatography;   

DOI  :  10.1016/0014-5793(87)81424-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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 α-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.

【 授权许可】

Unknown