title: Evidence for N-formyl chemotactic peptide-stimulated GTPase activity in human neutrophil homogenates.
abstract: Neutrophil homogenates contained a high affinity guanosine triphosphatase (GTPase) that was stimulatable (+27%) by the addition of 100 nM N-formyl chemotactic peptide (CHO-pep), but not by 1 microgram X ml-1 phorbolmyristate acetate (PMA). Kinetic analysis of the stimulation demonstrated an apparent lagtime of 14.3 +/- 6.9 s between the addition of CHO-pep and the optimal GTPase stimulation. The GTPase activity (but not CHO-pep-stimulated GTPase activity) was preserved in a highly purified plasma membrane fraction of the homogenate. From these observations we suggest that both a high affinity guanine nucleotide binding protein and GTPase are closely associated with the plasma membrane CHO-pep receptor. The possibility that GTPase activity may influence guanine nucleotide regulation of adenylate cyclase during CHO-pep stimulation of neutrophils is discussed.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D002474:Cell-Free System; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D019204:GTP-Binding Proteins; D006801:Humans; D007700:Kinetics; D009504:Neutrophils / Q000201:enzymology*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000502:physiology*; D044042:Receptors, Formyl Peptide
chemical_list: D011956:Receptors, Cell Surface; D044042:Receptors, Formyl Peptide; D010744:Phosphoric Monoester Hydrolases; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases