FIDELIO GERARDO DANIEL
Congresos y reuniones científicas
Título:
Activity profile of the first prokaryotic secretory phospholipase A2 acting on substrate monolayers
Autor/es:
YUNES QUARTINO P.J.; FIDELIO G.D.
Lugar:
TUCUMAN
Reunión:
Congreso; XLI REUNION ANUAL SOCIEDAD ARGENTINA DE BIOFISICA; 2012
Institución organizadora:
SOCIEDAD ARGENTINA DE BIOFISICA
Resumen:

Secretory phospholipases A2 (sPLA2s) are small (13-15KDa), highly disulfide-linked enzymes that hydrolyze the sn-2 ester bond of glycerophospholipids, requiring Ca2+ in the millimolar range for activity.  The most common features studied are head-group and chain length preferences. However, data on activity vs. lateral packing of lipid substrate is not frequently found in the literature. It has been shown that there could be a remarkable difference between enzymes and this is related to its ability to attack cell membranes.  E.g. sPLA2 from pig pancreas hydrolyses dlPC monolayers with a cut-off lateral pressure of 18 mN/m while cobra venom sPLA2  does it up to 30 mN/m. In turn, red blood cells are hydrolyzed by cobra sPLA2 but not by the enzyme of pancreatic origin.

In 2002 a sPLA2 was obtained from Streptomyces violaceoruber cultures (1). This was the first sPLA2 of prokaryotic origin described in the literature.

In this work we present the first steps to characterizing the activity of this enzyme in substrate monolayers of DLPC along with a comparison to the canonical enzyme models of  ?high? lateral pressure (cobra venom sPLA2) and ?low? lateral pressure (pig pancreatic sPLA2) enzymes. To obtain the cut-off and optimal pressures values we used the standard barostat technique, and a simpler constant area analysis. Both approaches produced very similar results.