Oblozinsky, M. Schoeps, R. Ulbrich-Hofmann, R. Bezakova, L. text xx 9999 monographic und

electronic

Phospholipase D (PLD)has been detected in seedlings of Papaver somniferum L. cv. Lazu´ r (Papaveraceae). Purification of the enzyme revealed the existence of two forms of PLD (named as PLD-A and PLD-B). The two enzymes strongly differ in their catalytic properties. The pH optima were found at pH 8.0 for PLD-A and at pH 5.5 for PLD-B. While both enzymes show hydrolytic activity toward phosphatidylcholine (PC)and phosphatidyl-p-nitrophenol (PpNP), PLD-B only was able to catalyze the exchange of choline in PC by glycerol. Both enzymes were activated by Ca2 + ions with an optimum concentration of 10 mM. In contrast to PLDs from other plants, LD-B was still more activated by Zn2 + ions with an optimum concentration of 5 mM. The apparent molecular masses of PLD-A and PLD-B, derived from sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE), were estimated to be 116.4 and 114.1 kDa. N-terminal protein sequencing indicated N-terminal blockage in both cases. The isoelectric points were found to be 8.7 for PLD-A and 6.7 for PLD-B. Both enzymes were shown to be N-linked glycoproteins. This paper is the first report on PLD in poppy and indicates some important differences of the two enzyme forms to other PLDs known so far. PHOSPHOLIPASE D PAPAVER SOMNIFERUM PURIFICATION ZN-ACTIVATION TRANSPHOSPHATIDYLATION https://drive.google.com/file/d/1Xmvhn1XCXbNqiSWKDEylY0DIrqQh8SGu/view?usp=drivesdk https://drive.google.com/file/d/1Xmvhn1XCXbNqiSWKDEylY0DIrqQh8SGu/view?usp=drivesdk 250602 20260521091343.0