Details

Autor(en) / Beteiligte

• Singer, Alan G
• Ghomashchi, Farideh
• Le Calvez, Catherine
• Bollinger, James
• Bezzine, Sofiane
• Rouault, Morgane
• Sadilek, Martin
• Nguyen, Eric
• Lazdunski, Michel
• Lambeau, Gerard
• Gelb, Michael H

Titel

Interfacial Kinetic and Binding Properties of the Complete Set of Human and Mouse Groups I, II, V, X, and XII Secreted Phospholipases A2

Ist Teil von

• The Journal of biological chemistry, 2002-12, Vol.277 (50), p.48535-48549

Ort / Verlag

United States: American Society for Biochemistry and Molecular Biology

Erscheinungsjahr

2002

Quelle

MEDLINE

Beschreibungen/Notizen

• Expression of the full set of human and mouse groups I, II, V, X, and XII secreted phospholipases A 2 (sPLA 2 s) in Escherichia coli and insect cells has provided pure recombinant enzymes for detailed comparative interfacial kinetic and binding studies. The set of mammalian sPLA 2 s display dramatically different sensitivity to dithiothreitol. The specific activity for the hydrolysis of vesicles of differing phospholipid composition by these enzymes varies by up to 4 orders of magnitude, and yet all enzymes display similar catalytic site specificity toward phospholipids with different polar head groups. Discrimination between sn -2 polyunsaturated versus saturated fatty acyl chains is <6-fold. These enzymes display apparent dissociation constants for activation by calcium in the 1–225 μ m range, depending on the phospholipid substrate. Analysis of the inhibition by a set of 12 active site-directed, competitive inhibitors reveals a large variation in the potency among the mammalian sPLA 2 s, with Me-Indoxam being the most generally potent sPLA 2 inhibitor. A dramatic correlation exists between the ability of the sPLA 2 s to hydrolyze phosphatidylcholine-rich vesicles efficiently in vitro and the ability to release arachidonic acid when added exogenously to mammalian cells; the group V and X sPLA 2 s are uniquely efficient in this regard.