[Study of phospholipase A2 specificity in substrate-containing structures having different supramolecular organization].
The specificity of snake venom phospholipase A2(PLA2) towards a number of phospholipid (PL) substrates, e. g., phosphatidylcholine (PC), phosphatidylglycerol (PG), phosphatidylethanolamine (PE) and phosphatidylinositol (PI) organized in Triton X-100 mixed micelles, liposomes and proteoliposomes was studied. PC was shown to be more rapidly hydrolyzed in micelles. For other PLs, the rate of hydrolysis decreased in the following sequence: PC greater than PI greater than PE greater than PG. The incorporation into micelles of a non-hydrolyzable by PLA2 sphinogomyelin which, similar to PC, has a choline group, resulted in an increase of PLA2 specificity towards PL that are known to be devoid of this group: PE greater than PI greater than PG greater than PC. Quite a different picture was observed in bilayer liposomal structures: PI congruent to PE greater than PC greater than PG. The incorporation of cytochrome P-450 into liposomes caused the acceleration of PE and PG hydrolysis. The course of the PLA2-catalyzed hydrolysis in model membrane structures seems to be governed primarily by the supramolecular organization and localization of the substrate in the bilayer, but not by its chemical structure.
A M
AM
Akhrem
T A
TA
Shumilina
N M
NM
Litvinko
O I
OI
Linnik
M A
MA
Kisel'
D000818:Animals; D004546:Elapid Venoms / Q000032:analysis; D006868:Hydrolysis; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D010743:Phospholipids / Q000032:analysis; D013379:Substrate Specificity
D004546:Elapid Venoms; D046911:Macromolecular Substances; D010743:Phospholipids; D010740:Phospholipases; D010741:Phospholipases A; D054467:Phospholipases A2
Izuchenie spetsifichnosti fosfolipazy A2 na substratsoderzhashchikh strukturakh, imeiushchikh raznuiu nadmolekuliarnuiu organizatsiiu.