“Al3+-mediated changes in membranes fluidity affects the activity of PI-PLC but not of PLC.”

SANDRA V. VERSTRAETEN; MARCELA S. VILLAVERDE; PATRICIA I. OTEIZA.

CHEMISTRY AND PHYSICS OF LIPIDS

Elsevier Science Ireland

Lugar: Ireland; Año: 2003 p. 159 - 163

0009-3084

Sandra V. Verstraeten, Marcela S. Villaverde, y Patricia I. Oteiza. “Al3+-mediated changes in membranes fluidity affects the activity of PI-PLC but not of PLC.” Chemistry and Physics of Lipids 122, 159-163 (2003). We investigated whetherAl3+-mediated changes in the membrane fluidity can affect the activity of prokaryotic enzymes phospholipase C (PLC) and phospholipase C-phosphatidyl specific (PI-PLC) in liposomes of phosphatidyl choline (PC), PC: phophatidyl inositol (PI), or PC and polyphosphoinositides (PPI). Al3+ (10-100 µM) promoted membrane rigidification, evaluated with the probes 1,6-diphenyl-1,3,5-hexatriene and Laurdan, and followed the order: PC:PPI› PC:PI› PC. Al3+ (25 and 50 µM) did not affect PLC-mediated hydrolysis of PC, PI and PIP2, but stimulated PIP hydrolysis (48.6 %). PI-PLC did not affect PC, PI, and PIP concentrations, but caused a 67 % decrease in PIP2. Al3+ significantly inhibited PIP2 hydrolysis in a concentration-dependent (25 and 50 µM) manner. Results suggest that the inhibited PIP2 hydrolysis by Al3+could be partially due to a higher lipid packing induced by Al3+ which could affect the interaction between the enzyme and its substrate.