title: Antibodies directed against synthetic peptides distinguish between GTP-binding proteins in neutrophil and brain.
abstract: Antisera AS/6 and 7, raised against a synthetic peptide KENLKDCGLF corresponding to the carboxyl-terminal decapeptide of transducin-alpha, react on immunoblots with purified transducin-alpha and with proteins of 40-41 kDa in all tissues tested. The latter represent one or more forms of Gi alpha but not Go alpha, since a synthetic peptide, KNNLKDCGLF, corresponding to the carboxyl-terminal decapeptide of two forms of Gi alpha blocks AS/6 and 7 reactivity with transducin-alpha and Gi alpha on immunoblots, whereas the corresponding Go-related peptide, ANNLRGCGLY, does not. Antisera LE/2 and 3, raised against the synthetic peptide LERIAQSDYI, corresponding to an internal sequence predicted by one form of Gi alpha cDNA (Gi alpha-2) and differing by 3 residues from the sequence of another form, Gi alpha-1, react strongly with a 40-kDa protein abundant in neutrophil membranes and with the major pertussis toxin substrate purified from bovine neutrophils. LE/2 and 3 reveal a relatively faint 40-kDa band on immunoblots of crude brain membranes or of purified brain Gi/Go. LE/2 and 3 do not react with transducin-alpha or Go alpha nor with the 41-kDa form of pertussis toxin substrate in brain, Gi alpha-1. These antisera distinguish between the major pertussis toxin substrates of brain and neutrophil and tentatively identify the latter as Gi alpha-2.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D019204:GTP-Binding Proteins / Q000032:analysis / Q000276:immunology*; D007106:Immune Sera / Q000276:immunology*; D008565:Membrane Proteins / Q000276:immunology; D009504:Neutrophils / Q000032:analysis*; D010446:Peptide Fragments / Q000276:immunology*; D037342:Pertussis Toxin; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism; D011817:Rabbits; D015293:Transducin; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D007106:Immune Sera; D008565:Membrane Proteins; D010446:Peptide Fragments; D010566:Virulence Factors, Bordetella; D011064:Poly Adenosine Diphosphate Ribose; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D015293:Transducin