Characterization of cytosolic phospholipase A2 in rat mastocytoma RBL-2H3.
We previously reported that cultured mast cells expressed three discrete phospholipases A2 (PLA2S), one of which showed a remarkable preference for phospholipids bearing an arachidonoyl residue at the sn-2 position [M. Murakami, et al., J. Biochem., 111, 175 (1992)]. In the present study, we have purified and characterized this enzyme using rat mastocytoma RBL-2H3 as an enzyme source. The elution profiles of the arachidonoyl-preferential PLA2 activity of rat mastocytoma RBL-2H3 cells on several column chromatographies were indistinguishable from those of 85-kDa cytosolic PLA2 (cPLA2) characterized so far. The molecular mass of the partially purified PLA2 was estimated to be about 90 kDa by gel filtration and it hydrolyzed arachidonate-containing phospholipids preferentially in the presence of submicromolar Ca2+ concentrations. Furthermore, it was immunoprecipitated with an anti-rabbit cPLA2 antibody almost completely. From these observations, we have concluded that the arachidonoyl-preferential PLA2 in mast cells belongs to the "cPLA2" family.
Nakatani
Y
Y
Department of Health Chemistry, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
Hara
S
S
Murakami
M
M
Kudo
I
I
Inoue
K
K
D000818:Animals; D000911:Antibodies, Monoclonal; D016718:Arachidonic Acid / Q000378:metabolism; D002850:Chromatography, Gel; D003600:Cytosol / Q000201:enzymology; D006868:Hydrolysis; D008407:Mast Cells / Q000201:enzymology*; D012515:Mast-Cell Sarcoma / Q000201:enzymology*; D008970:Molecular Weight; D010741:Phospholipases A / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D054467:Phospholipases A2; D011233:Precipitin Tests; D051381:Rats; D013379:Substrate Specificity; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D016718:Arachidonic Acid; D010741:Phospholipases A; D054467:Phospholipases A2