title: Partial characterization of GTP-binding proteins in Neurospora.
abstract: Six fractions of GTP-binding proteins separated by gel filtration of a mycelial extract containing membrane components of Neurospora crassa were partially characterized. [35S]GTP gamma S bound to GTP-binding protein was assayed by repeated treatments with a Norit solution and centrifugation. The binding of [35S]GTP gamma S to GTP-binding proteins was competitively prevented in the presence of 0.1 to 1 mM GTP but not in the presence of ATP. These GTP-binding proteins fractionated by the gel column had Km values of 20, 7, 4, 4, 80 and 2 nM. All six fractions of these GTP-binding proteins showed the capacity to be ADP-ribosylated by pertussis toxin.
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002850:Chromatography, Gel; D019204:GTP-Binding Proteins / Q000302:isolation & purification* / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D007700:Kinetics; D009491:Neurospora / Q000378:metabolism*; D009492:Neurospora crassa / Q000378:metabolism*; D013462:Sulfur Radioisotopes; D013873:Thionucleotides / Q000378:metabolism*
chemical_list: D013462:Sulfur Radioisotopes; D013873:Thionucleotides; D000246:Adenosine Diphosphate Ribose; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins