Direct activation of phospholipase A2 by GTP-binding protein in human peripheral polymorphonuclear leukocytes.
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.
Ando
M
M
2nd Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Furui
H
H
Suzuki
K
K
Taki
F
F
Takagi
K
K
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
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