title: The purification of a guanine nucleotide regulatory protein from rat brain membrane and the measurement of its GTPase.
abstract: A guanine nucleotide regulatory protein (G-protein) was purified to homogeneity from rat brain membrane though a series of chromatography runs, including DE-52 ion exchange, AcA-34 ultrogel, and octyl-Sepharose columns. The purified G-protein consisted of 3 subunits with molecular weights of 41000, 36000, and 8000, respectively. The alpha-subunit of the G-protein possessed high affinity GTP binding sites (k = 22.5 nmol/L) and GTPase activity (Km = 82.5 nmol/L, Vmax = 2.8 pmol/min/microgram protein), and it could be ADP-ribosylated by [adenylate-32P]-NAD in the presence of pertussis toxin. These results suggest that the purified protein was Gi-protein.
authors.affiliation: Institute of Basic Medical Sciences, CAMS, Beijing.
authors.forename: D
authors.initials: D
authors.lastname: Zhang
authors.forename: C
authors.initials: C
authors.lastname: Kwen-Jen
mesh_terms: D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D001923:Brain Chemistry; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification*; D006160:Guanosine Triphosphate / Q000378:metabolism; D008970:Molecular Weight; D051381:Rats
chemical_list: D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins