Enhancement of Agkistrodon piscivorus piscivorus venom phospholipase A2 activity toward phosphatidylcholine vesicles by lysolecithin and palmitic acid: Studies with fluorescent probes of membrane structure

Abstract

The activity of phospholipase A2 from snake venom to hydrolyze bilayers of phosphatidylcholines is greatly enhanced by the presence of the hydrolysis products, lysolecithin and fatty acid, in the bilayer. The fluorescence of several probes of membrane structure was used to monitor changes in bilayer physical properties during vesicle hydrolysis. These changes were compared to emission spectra and fluorescence polarization results occurring upon direct addition of lysolecithin and/or fatty acid to the bilayer. The excimer to monomer ratio of 1,3-bis(1-pyrene)propane was insensitive to vesicle hydrolysis, suggesting that changes in the order of the phospholipid chains were not relevant to the effect of the hydrolysis products on phospholipase activity. The fluorescence of 6-propionyl-2-(dimethylamino)-naphthalene (Prodan) suggested that the polarity of the bilayer in the region of the phospholipid head groups increases as the hydrolysis products accumulate in the bilayer. The fluorescence of 6-dodecanoyl-2-(dimethylamino)naphthalene (Laurdan) confirmed that such effects were restricted to the bilayer surface. Furthermore, the lysolecithin appeared to be the product most responsible for these changes. These results suggested that lysolecithin increases the activity of phospholipase A2 during vesicle hydrolysis by disrupting the bilayer surface, making the phospholipid molecules more accessible to the enzyme active site.

Different modulation of phospholipase A2 activity by saturated and monounsaturated N-acylethanolamines

“…Laurdan and Prodan are similar probes that differ only in the length of their hydrophobic tail (12 C and 3 C atoms, respectively). The use of (21,24,26). In the presence of zwitterionic PL vesicles, PLA 2 activity is characterized by a latency period (identified as or lag time) of slow rate, followed by an abrupt increase of the hydrolytic rate.…”

“…For the first time, the effect due to NAEs differing for acyl chain length and unsaturation will be characterized on one-component liposomes of dipalmitoylphosphatidylcholine (DPPC) chosen to compare results obtained with recent papers on PLA 2 activity modulation by lipid surface (21,24,(26)(27)(28). In fact, many details (e.g., the temperature dependence of the enzymatic rate) were cleared in DPPC large unilamellar vesicles (LUVs) so that these vesicles are used as a fairly simple model system for investigating the delicate interplay between the PLA 2 activity and the physicochemical features of lipid bilayers (29,30).…”

Relationship between Erythrocyte Membrane Phase Properties and Susceptibility to Secretory Phospholipase A2

“…Properties that promote susceptibility include negative charge in the membrane surface, high curvature of the bilayer, and heterogeneity of lipid components (3)(4)(5)(6)(7)(8)(9)(10). Furthermore, the activity of sPLA 2 is extremely sensitive to the level of ordering of membrane lipids (3,4,6,7,11).…”

Phospholipase А2 purification and characterization from venom of snake Gloydius blomhoffii brevicaudus

“…Elution was performed by line gradient (9-75)×10 3 S×сm -1 of NaCl in 20×10 3 М Na acetic buffer, рН 3.6, with a flow rate of 5 ml×min -1 ; Б -sample was applied to RESOURCE 3 ml column in 10×10 3 М NaOH, containing 2% of acetonitrile (buffer А), рН 3.6, with a flow rate of 1 ml×min -1 . Elution was performed by line gradient of buffer B (10×10 3 М NaOH, containing 80% of acetonitrile) in buffer A with a flow rate of 1 ml×min -1 [43,44,50].…”