title: Direct activation of phospholipase A2 by GTP-binding protein in human peripheral polymorphonuclear leukocytes.
abstract: In human peripheral polymorphonuclear leukocyte (PMN), 10% of PLA2 activity was found in the particulate fraction. In the particulate fraction, the activity of phospholipase A2 was enhanced 270% by 100 microM guanosine 5'-[gamma-thio]triphosphate, a hydrolysis-resistant analog of GTP. In the soluble fraction, such enhancement was not observed. Guanosine 5'-[beta-thio]diphosphate (2 mM), which irreversibly inactivates GTP-binding protein, blocked the enhancement in the particulate fraction. Membrane-binding phospholipase A2 activity of PMN would thus appear to be regulated directly by GTP-binding protein.
authors.affiliation: 2nd Department of Internal Medicine, Nagoya University School of Medicine, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ando
authors.forename: H
authors.initials: H
authors.lastname: Furui
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: F
authors.initials: F
authors.lastname: Taki
authors.forename: K
authors.initials: K
authors.lastname: Takagi
mesh_terms: D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D008566:Membranes / Q000201:enzymology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000201:enzymology*; D010741:Phospholipases A / Q000187:drug effects / Q000378:metabolism*; D054467:Phospholipases A2; D013347:Subcellular Fractions / Q000201:enzymology; D013873:Thionucleotides / Q000494:pharmacology
chemical_list: D013873:Thionucleotides; D006153:Guanosine Diphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D009240:N-Formylmethionine Leucyl-Phenylalanine; C023427:guanosine 5'-O-(2-thiodiphosphate); D010741:Phospholipases A; D054467:Phospholipases A2; D019204:GTP-Binding Proteins