INVESTIGADORES
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.