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lipid II complex lipids.pptx

  1. Moazzam Ali Shahid Senior Lecturer (Molecular Medicine) Senior Research Officer (Research) PhD Scholar (Biochemistry)
  2.  Esters of fatty acids containing groups in addition to an alcohol and a fatty acid. 1-PHOSPHOLIPIDS: A-glycerophospholipids the alcohol is glycerol B-sphingophospholipids the alcohol is sphingosine. Example Plasmalogens: They are highly abundant in the neuronal, immune, and cardiovascular cell membranes. .Phosphatidylcholine
  3.  A lecithin CH2 CH CH2 O O O O O P OCH2 CH2 N( CH3) 3 O O- + palmitic acid stearic acid glycerol choline
  4.  Lecithin is a mixture of fats that are essential to cells in the human body. It can be found in many foods, including soybeans and egg yolks.
  5.  Hydrophobic or hydrophilic? ◦ fatty acid tails = hydrophobic ◦ PO4 = hydrophilic head ◦ dual “personality” interaction with H2O is complex & very important!
  6.  Hydrophilic heads attracted to H2O  Hydrophobic tails “hide” from H2O ◦ can self-assemble into “bubbles”  bubble = “micelle”  can also form bilayer bilayer
  7.  Phospholipids create a barrier in water ◦ define outside vs. inside ◦ cell membranes
  8. C OH H CH2OH CH2OH glycerol Glycerophospholipids (phosphoglycerides), are common constituents of cellular membranes. They have a glycerol backbone. Hydroxyls at C1 & C2 are esterified to fatty acids. An ester forms when a hydroxyl reacts with a carboxylic acid, with loss of H2O. Formation of an ester: O O R'OH + HO-C-R" R'-O-C-R'' + H2O
  9. In phosphatidate:  fatty acids are esterified to hydroxyls on C1 & C2  the C3 hydroxyl is esterified to Pi. O P O O O H2C CH H2C O C R1 O O C O R2 phosphatidate
  10. O P O O O H2C CH H2C O C R1 O O C O R2 X glycerophospholipid In most glycerophospholipids (phosphoglycerides), Pi is in turn esterified to OH of a polar head group (X): e.g., serine, choline, ethanolamine,
  11.  Sphingosine is formed by an amino alcohol head group, with two hydroxyls, and one amino group attached to a long unsaturated hydrocarbon chain of typically 18 carbon atoms H2C H C OH CH N+ CH C CH2 CH3 H H3 OH ( )12 sphingosine
  12.  Glycolipid: a compound in which a carbohydrate is bound to an -OH of the lipid ◦ many glycolipids are derived from ceramides O ( CH2 ) 12 CH3 HO NHCR O O H HO H HO H H OH H OH a-glucoside bond a unit of -D-glucopyranose
  13. Cerebrosides and gangliosides, collectively called glycosphingolipids, are commonly found in the outer leaflet of the plasma membrane bilayer, with their sugar chains extending out from the cell surface. cerebroside with -galactose head group H2C H C CH NH CH C CH2 CH3 OH C R O OH O H H H OH H OH CH2OH H O H ( )12 • A cerebroside is a sphingolipid (ceramide) with a monosaccharide such as glucose or galactose as polar head group. • A ganglioside is a ceramide with a polar head group that is a complex oligosaccharide, including the acidic sugar derivative sialic acid.
  14.  Sphingomyelins have phosphocholine or phosp hoethanolamine molecule with an ester linkage to the 1-hydroxy group of a ceramide.
  15. OH ( CH2 ) 12 CH3 HO NH2 Sphingosine OH ( CH2 ) 12 CH3 HO NHCR A ceramide (an N-acylsphingosine) OPOCH2 CH2 N( CH3 ) 3 ( CH2 ) 12 CH3 HO NHCR A sphingomyelin O O O O- +
  16.  Glycosphingolipids are ceramides with one or more sugar residues joined in a β- glycosidic linkage at the 1-hydroxyl position  Cerebrosides have a single glucose or galactose at the 1-hydroxy position.  Sulfatides are sulfated cerebrosides.  Gangliosides have at least three sugars, one of which must be sialic acid.