Skip to main content
PMC home page
Biochemical Journal logoLink to Biochemical Journal
. 2001 Jul 15;357(Pt 2):457–464. doi: 10.1042/0264-6021:3570457

Platelet-activating factor acetylhydrolase and transacetylase activities in human plasma low-density lipoprotein.

D C Tsoukatos 1, T A Liapikos 1, A D Tselepis 1, M J Chapman 1, E Ninio 1
PMCID: PMC1221972  PMID: 11439095

Abstract

In this study, we demonstrate the presence of a transacetylase activity in human plasma low-density lipoprotein (LDL) that transfers short-chain fatty acids from platelet-activating factor (PAF) and its close ether- and ester-linked analogues to ether/ester-linked lysophospholipids (lyso-PL). We show evidence that both PAF acetylhydrolase (PAF-AH) and transacetylase activities are inhibited to the same extent by serine esterase inhibitors, are resistant to heat treatment, and exhibit identical distributions in lipoprotein classes and in LDL subfractions. Additionally, the competitive inhibition of PAF-AH by lyso-PL, and the evidence that the recombinant PAF-AH also showed a similar transacetylase activity, suggest that PAF-AH is responsible for both activities. Using PAF as a donor molecule and lyso-PAF (1-O-alkyl-sn-glycero-3-phosphocholine) as an acceptor, the transacetylase activity showed typical allosteric kinetics, due to the positive co-operativity of the substrates, with apparent Vmax=19.6+/-3.4 nmol/min per mg of protein, apparent h=2.0+/-0.3 and apparent [S]0.5=9.4+/-2.3 microM at saturation for the concentration of lyso-PAF. The substrate specificity of the donor molecules was decreased by increasing the chain length of the acyl moiety in the sn-2 position of the glycerol. The ether linkage in the sn-1 position of the substrate was 30% more effective than the ester bond; cholesteryl acetate was inactive as an acetyl donor. The two acceptors tested, lyso-PAF and the ester-linked lyso-PC (1-acyl-sn-glycero-3-phosphocholine), showed similar specificity. Addition of exogenous lyso-PAF induced the transient formation of PAF-like aggregating activity predominantely in small dense LDL subfractions upon oxidation. We conclude that PAF-AH possesses both transacetylase and acetylhydrolase activities which remove PAF and its ether-linked analogues from LDL particles upon LDL oxidation. However, in atherogenic small dense LDL-5 particles, the transacetylase activity may acetylate extracellular lyso-PAF into biologically active PAF.

Full Text

The Full Text of this article is available as a PDF (182.9 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Aron L., Jones S., Fielding C. J. Human plasma lecithin-cholesterol acyltransferase. Characterization of cofactor-dependent phospholipase activity. J Biol Chem. 1978 Oct 25;253(20):7220–7226. [PubMed] [Google Scholar]
  2. BARTLETT G. R. Phosphorus assay in column chromatography. J Biol Chem. 1959 Mar;234(3):466–468. [PubMed] [Google Scholar]
  3. BLIGH E. G., DYER W. J. A rapid method of total lipid extraction and purification. Can J Biochem Physiol. 1959 Aug;37(8):911–917. doi: 10.1139/o59-099. [DOI] [PubMed] [Google Scholar]
  4. Bae K., Longobardi L., Karasawa K., Malone B., Inoue T., Aoki J., Arai H., Inoue K., Lee T. Platelet-activating factor (PAF)-dependent transacetylase and its relationship with PAF acetylhydrolases. J Biol Chem. 2000 Sep 1;275(35):26704–26709. doi: 10.1074/jbc.M003951200. [DOI] [PubMed] [Google Scholar]
  5. Benveniste J., Le Couedic J. P., Polonsky J., Tence M. Structural analysis of purified platelet-activating factor by lipases. Nature. 1977 Sep 8;269(5624):170–171. doi: 10.1038/269170a0. [DOI] [PubMed] [Google Scholar]
  6. Blank M. L., Lee T., Fitzgerald V., Snyder F. A specific acetylhydrolase for 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine (a hypotensive and platelet-activating lipid). J Biol Chem. 1981 Jan 10;256(1):175–178. [PubMed] [Google Scholar]
  7. Bossant M. J., Ninio E., Delautier D., Benveniste J. Bioassay of paf-acether by rabbit platelet aggregation. Methods Enzymol. 1990;187:125–130. doi: 10.1016/0076-6879(90)87016-v. [DOI] [PubMed] [Google Scholar]
  8. Caslake M. J., Packard C. J., Suckling K. E., Holmes S. D., Chamberlain P., Macphee C. H. Lipoprotein-associated phospholipase A(2), platelet-activating factor acetylhydrolase: a potential new risk factor for coronary artery disease. Atherosclerosis. 2000 Jun;150(2):413–419. doi: 10.1016/s0021-9150(99)00406-2. [DOI] [PubMed] [Google Scholar]
  9. Chapman M. J., Goldstein S., Lagrange D., Laplaud P. M. A density gradient ultracentrifugal procedure for the isolation of the major lipoprotein classes from human serum. J Lipid Res. 1981 Feb;22(2):339–358. [PubMed] [Google Scholar]
  10. Chapman M. J., Guérin M., Bruckert E. Atherogenic, dense low-density lipoproteins. Pathophysiology and new therapeutic approaches. Eur Heart J. 1998 Feb;19 (Suppl A):A24–A30. [PubMed] [Google Scholar]
  11. Dentan C., Lesnik P., Chapman M. J., Ninio E. PAF-acether-degrading acetylhydrolase in plasma LDL is inactivated by copper- and cell-mediated oxidation. Arterioscler Thromb. 1994 Mar;14(3):353–360. doi: 10.1161/01.atv.14.3.353. [DOI] [PubMed] [Google Scholar]
  12. Dentan C., Tselepis A. D., Chapman M. J., Ninio E. Pefabloc, 4-[2-aminoethyl]benzenesulfonyl fluoride, is a new, potent nontoxic and irreversible inhibitor of PAF-degrading acetylhydrolase. Biochim Biophys Acta. 1996 Feb 16;1299(3):353–357. doi: 10.1016/0005-2760(95)00226-x. [DOI] [PubMed] [Google Scholar]
  13. Evangelou A. M. Platelet-activating factor (PAF): implications for coronary heart and vascular diseases. Prostaglandins Leukot Essent Fatty Acids. 1994 Jan;50(1):1–28. doi: 10.1016/0952-3278(94)90101-5. [DOI] [PubMed] [Google Scholar]
  14. Glomset J. A. The plasma lecithins:cholesterol acyltransferase reaction. J Lipid Res. 1968 Mar;9(2):155–167. [PubMed] [Google Scholar]
  15. Goyal J., Wang K., Liu M., Subbaiah P. V. Novel function of lecithin-cholesterol acyltransferase. Hydrolysis of oxidized polar phospholipids generated during lipoprotein oxidation. J Biol Chem. 1997 Jun 27;272(26):16231–16239. doi: 10.1074/jbc.272.26.16231. [DOI] [PubMed] [Google Scholar]
  16. Karakatsani A. I., Liapikos T. A., Troganis A. N., Tsoukatos D. C. Involvement of phospholipids in apolipoprotein B modification during low density lipoprotein oxidation. Lipids. 1998 Dec;33(12):1159–1162. doi: 10.1007/s11745-998-0318-3. [DOI] [PubMed] [Google Scholar]
  17. Kelley J. L., Alaupovic P. Lipid transport in the avian species. Part I. Isolation and characterization of apolipoproteins and major lipoprotein density classes of male turkey serum. Atherosclerosis. 1976 Jul-Aug;24(1-2):155–175. doi: 10.1016/0021-9150(76)90073-3. [DOI] [PubMed] [Google Scholar]
  18. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  19. Lekka M. E., Tsoukatos D. C., Tselepis A. D., Kapoulas V. M. Semisynthetic preparation of 1-O-hexadecyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (platelet activating factor). Z Naturforsch C. 1988 Sep-Oct;43(9-10):665–670. doi: 10.1515/znc-1988-9-1007. [DOI] [PubMed] [Google Scholar]
  20. Liapikos T. A., Antonopoulou S., Karabina S. P., Tsoukatos D. C., Demopoulos C. A., Tselepis A. D. Platelet-activating factor formation during oxidative modification of low-density lipoprotein when PAF-acetylhydrolase has been inactivated. Biochim Biophys Acta. 1994 Jun 2;1212(3):353–360. doi: 10.1016/0005-2760(94)90210-0. [DOI] [PubMed] [Google Scholar]
  21. Liu M., Subbaiah P. V. Hydrolysis and transesterification of platelet-activating factor by lecithin-cholesterol acyltransferase. Proc Natl Acad Sci U S A. 1994 Jun 21;91(13):6035–6039. doi: 10.1073/pnas.91.13.6035. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. MacPhee C. H., Moores K. E., Boyd H. F., Dhanak D., Ife R. J., Leach C. A., Leake D. S., Milliner K. J., Patterson R. A., Suckling K. E. Lipoprotein-associated phospholipase A2, platelet-activating factor acetylhydrolase, generates two bioactive products during the oxidation of low-density lipoprotein: use of a novel inhibitor. Biochem J. 1999 Mar 1;338(Pt 2):479–487. [PMC free article] [PubMed] [Google Scholar]
  23. Marathe G. K., Davies S. S., Harrison K. A., Silva A. R., Murphy R. C., Castro-Faria-Neto H., Prescott S. M., Zimmerman G. A., McIntyre T. M. Inflammatory platelet-activating factor-like phospholipids in oxidized low density lipoproteins are fragmented alkyl phosphatidylcholines. J Biol Chem. 1999 Oct 1;274(40):28395–28404. doi: 10.1074/jbc.274.40.28395. [DOI] [PubMed] [Google Scholar]
  24. Morel D. W., Hessler J. R., Chisolm G. M. Low density lipoprotein cytotoxicity induced by free radical peroxidation of lipid. J Lipid Res. 1983 Aug;24(8):1070–1076. [PubMed] [Google Scholar]
  25. Mueller H. W., Nollert M. U., Eskin S. G. Synthesis of 1-acyl-2-[3H]acetyl-SN-glycero-3-phosphocholine, a structural analog of platelet activating factor, by vascular endothelial cells. Biochem Biophys Res Commun. 1991 May 15;176(3):1557–1564. doi: 10.1016/0006-291x(91)90465-j. [DOI] [PubMed] [Google Scholar]
  26. Nidorf S. M., Sturm M., Strophair J., Kendrew P. J., Taylor R. R. Whole blood aggregation, thromboxane release and the lyso derivative of platelet activating factor in myocardial infarction and unstable angina. Cardiovasc Res. 1989 Apr;23(4):273–278. doi: 10.1093/cvr/23.4.273. [DOI] [PubMed] [Google Scholar]
  27. Packard C. J., O'Reilly D. S., Caslake M. J., McMahon A. D., Ford I., Cooney J., Macphee C. H., Suckling K. E., Krishna M., Wilkinson F. E. Lipoprotein-associated phospholipase A2 as an independent predictor of coronary heart disease. West of Scotland Coronary Prevention Study Group. N Engl J Med. 2000 Oct 19;343(16):1148–1155. doi: 10.1056/NEJM200010193431603. [DOI] [PubMed] [Google Scholar]
  28. Ross R. The pathogenesis of atherosclerosis: a perspective for the 1990s. Nature. 1993 Apr 29;362(6423):801–809. doi: 10.1038/362801a0. [DOI] [PubMed] [Google Scholar]
  29. Satouchi K., Oda M., Saito K. 1-Acyl-2-acetyl-sn-glycero-3-phosphocholine from stimulated human polymorphonuclear leukocytes. Lipids. 1987 Apr;22(4):285–287. doi: 10.1007/BF02533994. [DOI] [PubMed] [Google Scholar]
  30. Smith P. K., Krohn R. I., Hermanson G. T., Mallia A. K., Gartner F. H., Provenzano M. D., Fujimoto E. K., Goeke N. M., Olson B. J., Klenk D. C. Measurement of protein using bicinchoninic acid. Anal Biochem. 1985 Oct;150(1):76–85. doi: 10.1016/0003-2697(85)90442-7. [DOI] [PubMed] [Google Scholar]
  31. Snyder F. Platelet-activating factor and its analogs: metabolic pathways and related intracellular processes. Biochim Biophys Acta. 1995 Feb 9;1254(3):231–249. doi: 10.1016/0005-2760(94)00192-2. [DOI] [PubMed] [Google Scholar]
  32. Stafforini D. M., McIntyre T. M., Carter M. E., Prescott S. M. Human plasma platelet-activating factor acetylhydrolase. Association with lipoprotein particles and role in the degradation of platelet-activating factor. J Biol Chem. 1987 Mar 25;262(9):4215–4222. [PubMed] [Google Scholar]
  33. Steinbrecher U. P., Pritchard P. H. Hydrolysis of phosphatidylcholine during LDL oxidation is mediated by platelet-activating factor acetylhydrolase. J Lipid Res. 1989 Mar;30(3):305–315. [PubMed] [Google Scholar]
  34. Subbaiah P. V., Albers J. J., Chen C. H., Bagdade J. D. Low density lipoprotein-activated lysolecithin acylation by human plasma lecithin-cholesterol acyltransferase. Identity of lysolecithin acyltransferase and lecithin-cholesterol acyltransferase. J Biol Chem. 1980 Oct 10;255(19):9275–9280. [PubMed] [Google Scholar]
  35. Triggiani M., Schleimer R. P., Warner J. A., Chilton F. H. Differential synthesis of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine and platelet-activating factor by human inflammatory cells. J Immunol. 1991 Jul 15;147(2):660–666. [PubMed] [Google Scholar]
  36. Tselepis A. D., Dentan C., Karabina S. A., Chapman M. J., Ninio E. PAF-degrading acetylhydrolase is preferentially associated with dense LDL and VHDL-1 in human plasma. Catalytic characteristics and relation to the monocyte-derived enzyme. Arterioscler Thromb Vasc Biol. 1995 Oct;15(10):1764–1773. doi: 10.1161/01.atv.15.10.1764. [DOI] [PubMed] [Google Scholar]
  37. Tsoukatos D. C., Arborati M., Liapikos T., Clay K. L., Murphy R. C., Chapman M. J., Ninio E. Copper-catalyzed oxidation mediates PAF formation in human LDL subspecies. Protective role of PAF:acetylhydrolase in dense LDL. Arterioscler Thromb Vasc Biol. 1997 Dec;17(12):3505–3512. doi: 10.1161/01.atv.17.12.3505. [DOI] [PubMed] [Google Scholar]
  38. Witztum J. L., Steinberg D. Role of oxidized low density lipoprotein in atherogenesis. J Clin Invest. 1991 Dec;88(6):1785–1792. doi: 10.1172/JCI115499. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. van Heusden G. P., Vianen G. M., van den Bosch H. Differentiation between acyl coenzyme A:lysophosphatidylcholine acyltransferase and lysophosphatidylcholine: lysophosphatidylcholine transacylase in the synthesis of dipalmitoylphosphatidylcholine in rat lung. J Biol Chem. 1980 Oct 10;255(19):9312–9318. [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES