Lipids

1. Lipids Prof.Dr.Gülden Burçak 2011-2012

2. Heterogenousgroup • Insoluble in water, soluble in nonpolarsolvents • Dietaryconstituents • Adiposetissue • Myelinatednerves • Lipoproteins • Obesity, diabetesmellitus, atherosclerosis

4. 1)Simplelipids Fats Waxes 2)Complexlipids Phospholipids Glycolipids (glycosphingolipids) Sulfolipids,aminolipids,lipoproteins 3)Precursorandderivedlipids Fattyacids, glycerol, steroids, other alcohols, fattyaldehydes, ketonebodies, hydrocarbons, lipid-solublevitamins, hormones

5. Simple lipids • Fats : Esters of fattyacidswithglycerol A fat in theliquidstate : oil • Waxes :Esters of fattyacidswithhighermolecularweightmonohydricalcohols

6. Unchargedlipidsarecalledneutrallipids • Acylglycerols • Cholesterol • Cholesterylesters

7. Fatty acids • Esterified and unesterified • Even numbered, straight-chain derivatives • Saturated and unsaturated

8. Nomenclature • -oic, -anoic, -enoic • Numberedfromthecarboxylcarbon (carbon no 1) • α, ß, γ……………..ω ( terminal CH3carbon) • ∆ : numberandposition of doublebonds • ∆9 :doublebondbetween C 9 and C10 • ω9:doublebond on C 9 countingfromtheωC ; ω9, ω6, ω3

9. Saturatedfattyacids

10. Unsaturated fatty acids • 1)Monounsaturated • 2)Polyunsaturated • 3)Eicosanoids • derivedfromeicosa (20C) polyenoicfattyacids : prostanoids,leukotrienesandlipoxins

12. Oleic acid

14. Essential fatty acids • Linoleicacid (ω-6) • α-Linolenicacid (ω-3) • Arachidonicacid (ω-6) can be formedfromlinoleicacid.

15. Geometric isomerism

16. Naturallyoccuringunsaturatedfattyacids • arenearlyall of cisconfiguration • L-shaped • A highnumber of cisdoublebondsleadsto a variety of possiblespatialconfigurations • Arachidonicacidwithfourcisdoublebonds has kinksor U shape • Spatialrelationships in plasmamembranephospholipidsareimportant • Trans fattyacidsdisturbthespatialrelationships

17. Melting point • Chain length • Degree of unsaturation • Membrane lipids are more unsaturated than storage lipids.

18. Eicosanoids • Parentcompound :C20polyunsaturatedfattyacids • Physiologicallyandpharmacologicallyactivecompounds • Prostanoids • prostaglandins (PGs) • prostacyclins (PGIs) • thromboxanes (TXs) • Leukotrienes (LTs) • Lipoxins (LXs)

20. Prostaglandinscausecontraction of smoothmusclecells • Prostacyclinsarepotentinhibitors of plateletaggregation • Thromboxanescausevasoconstrictionandplateletaggregation • Leukotrienesandlipoxinsarepotentregulators of manydiseaseprocesses • Leukotrienesarepotentproinflammatoryagents

22. Prostaglandin E2 Thromboxane A2 LeukotrieneA4

23. Triacylglycerols : Storage Mixed triacylglycerol 1,3-Distearopalmitin

24. Phospholipids 1) Phosphatidicacidandphosphatidylglycerol 2) Phosphatidylcholine 3) Phosphatidylethanolamine 4) Phosphatidylinositol 5) Phosphatidylserine 6) Lysophospholipids 7) Plasmalogens 8)Sphingomyelins

25. Phosphatidic acid

26. Phosphatidylcholines • Mostabundant in theplasmamembrane • Saturatedacylradical in C1positionandunsaturated in the C2 • Choline: hepaticlipoproteinsynthesisandexport ; acetylcholine

27. Dipalmitoyllecithin • Surface-activeagent (surfactant) in thelung • Alveolarwallsare not strongenoughtomaintaintheirshapeagainstthesurfacetension of water. • Dipalmitoyllecithinandsphingomyelinssecretedtothelungchamberpreventtheadherence of theinnersurfaces of thealveoli • Respiratorydistresssyndrome

28. Phosphatidylserine

29. Phosphatidylethanolamine

30. Phosphatidylinositol Phosphatidylinositol 4,5-bisphosphate : a precursor of second messengers

31. Diphosphatidylglycerol (Cardiolipin) Mitochondrial membranes

32. Lysolecithin • Lysophospholipids : important in the metabolism and interconversion of phosholipids. • Phospholipase A2 : formation of a lysophospholipid

33. Plasmalogens • Brain and muscle tissue

34. Sphingomyelins • Brainandnervetissue

35. Glycolipids • In cell surface carbohydrates • Particularly in the nervous tissue • Glycosphingolipids • Galactosylceramide : neural tissues • Glucosylceramide : extraneural tissues

36. Galactosylceramide (Galactocerebroside) • Brainandothernervoustissue • C24 : lignoceric, cerebronic , nervonic , oxynervonicacids • Sulfogalactosylceramide (sulfatide) : myelin

37. Fatty acids in cerebrosides

38. Gangliosides • Complex glycosphingolipids • Glucosylceramide + one or more sialic acids • Nervous tissue

39. Sialic acid : N-acetyl neuraminic acid Neuraminicacid : 9Csugarderivedfrommannosamineandpyruvate

40. GM1ganglioside : Monosialoganglioside

41. Steroids • Thesterane ring Cyclopentanoperhydrophenanthrene, a tetracyclichydrocarbon • Steroidnucleus

42. Chair and boat conformation

43. Cis-trans configuration

44. Cholesterol • Widely distributed in all cells,particularly in the nervous tissue • Plasma membrane and lipoproteins • In animal fats • Reduction of double bond : coprostanol (coprosterol)

45. Esterification of cholesterol at C3

46. Cholicacid : A cholesterolderivative

47. Steroid hormones

48. Ergosterol A precursor of vitamin D

49. Isopreneandpolyprenoids : dolichol, ubiquinone C95 alcohol

50. Plant derived isoprenoids • Fatsolublevitamins • Vitamin A • Vitamin D • Vitamin E • Vitamin K