Immunochemical evidence for a novel pertussis toxin substrate in human neutrophils.

摘要: Pertussis toxin catalyzes incorporation of 20.2 pmol ADP-ribose/mg protein into approximately 40-kDa protein(s) in human neutrophil membranes compared with 14.1 pmol/mg bovine brain membranes. Based on these measurements we estimate that pertussis substrate(s) should represent at least 0.085% total membrane neutrophils. Both and show high concentrations (0.34 versus 0.16% protein, respectively) the common beta subunit guanine nucleotide binding proteins. Affinity purified antibodies specific for Go-alpha fail to detect any immunoblots (150 micrograms) under conditions where as little 10 ng is detectable, readily detected (100 micrograms). An antiserum against transducin cross-reacts strongly Gi-alpha, detects 5 Gi-alpha membranes, but an band corresponds less than 10% expected amount substrate(s). The results contain relatively large amounts substrate(s), predominant substrate immunochemically distinct from previously identified substrates, transducin, Gi, Go.