Regulation of brain glycosylphosphatidylinositol-specific phospholipase D by natural amphiphiles.
Brain glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD)-catalyzed conversion of amphiphilic form of Zn2+ -glycerophosphocholine cholinephosphodiesterase (Amp-GPC PDE) into hydrophilic form was investigated in the presence of natural amphiphiles. Monoacylglycerols enhanced considerably the conversion by GPI-PLD of Amp-GPC PDE to hydrophilic form, with the enhancing effect of monoacylglycerols being dependent on the size of acyl group (C8-C18). Whereas the maximal enhancement of GPI-PLD action was the greatest with monodecanoylglycerol, the concentration (EC50) required to achieve 50% maximal effect was the smallest for monomyristoyl- or monopalmitoylglycerol. In addition, monolaurylglycerol or its alkyl analogue, monododecylglycerol, showed a remarkable decrease in enhancing effect at high concentrations (>1 mM). Presence of double bond in acyl chain, as exemplified by monooleoylglycerol or mono-11-eicosenoin, further enhanced the conversion by GPI-PLD. Meanwhile, lysophosphatidylcholine (IC50, 25 microM) and phosphatidic acid (IC50, >100 microM), ionic amphiphiles, inhibited the GPI-PLD activity, which was determined in the presence of monooleoylglycerol as a detergent. From these results, it is suggested that the activity of GPI-PLD in vivo system may be regulated by natural amphiphiles.
Lee
J Y
JY
College of Pharmacy, Chungnam National University, Taejon, Korea.
Lee
H J
HJ
Kim
M R
MR
Myung
P K
PK
Sok
D E
DE
D000818:Animals; D001921:Brain / Q000201:enzymology*; D002417:Cattle; D005989:Glycerides / Q000378:metabolism*; D007700:Kinetics; D010739:Phospholipase D / Q000302:isolation & purification / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D013379:Substrate Specificity; D015032:Zinc / Q000378:metabolism
D005989:Glycerides; D010727:Phosphoric Diester Hydrolases; C061931:glycerophosphocholine cholinephosphodiesterase; D010739:Phospholipase D; C065017:glycoprotein phospholipase D; D015032:Zinc