In vitro distribution and characterization of membrane-associated PLD and PI-PLC in Brassica napus.
Two types of phospholipid degrading enzyme, phospholipase D (PLD; EC 3.1.4.4) and phosphatidyl- inositol-specific phospholipase C (PIP(2)-PLC; PI-PLC 3.1.4.11) were studied during the development of seeds and plants of Brassica napus. PLD exhibits two types of activity; polyphosphoinositide-requiring (PIP(2)-dependent PLD) and polyphosphoinositide-independent requiring millimolar concentrations of calcium (PLDalpha). Significantly different patterns of activity profiles were found for soluble and membrane-associated forms of all three enzymes within both processes. Membrane-associated PIP(2)-dependent PLD activity shows the opposite trend when compared to PLDalpha, while the highest PI-PLC activity appears in the same stages of development of seeds and plants as for PLDalpha. In subcellular fractions of hypocotyls of young plants, phospholipases were localized predominantly on plasma membranes. The biochemical characteristics (Ca(2+), pH) of all three enzymes associated with plasma membrane vesicles, isolated by partitioning in an aqueous dextran- polyethylene glycol two-phase system, are also described. Direct interaction of PLDalpha with G-proteins under in vitro conditions was not confirmed.
Novotná
Zuzana
Z
Department of Biochemistry and Microbiology, Institute of Chemical Technology Prague, 166 28 Prague 6, Czech Republic.
Martinec
Jan
J
Profotová
Bronislava
B
Zdárová
Stĕpánka
S
Kader
Jean-Claude
JC
Valentová
Olga
O
D029688:Brassica napus / Q000201:enzymology* / Q000254:growth & development; D002118:Calcium / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D002734:Chlorophyll / Q000378:metabolism; D018548:Cotyledon / Q000201:enzymology / Q000254:growth & development; D019204:GTP-Binding Proteins / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D018546:Hypocotyl / Q000201:enzymology / Q000254:growth & development; D008565:Membrane Proteins / Q000378:metabolism; D054801:Phosphoinositide Phospholipase C; D010739:Phospholipase D / Q000187:drug effects / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000187:drug effects / Q000378:metabolism*; D012639:Seeds / Q000201:enzymology / Q000254:growth & development
D008565:Membrane Proteins; D002734:Chlorophyll; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D010727:Phosphoric Diester Hydrolases; D054801:Phosphoinositide Phospholipase C; D010739:Phospholipase D; D019204:GTP-Binding Proteins; D002118:Calcium