LIPIDS Daniel Bučánek Jan Gembík. Lipids Fatty acids Glycerides Nonglycerol lipids Complex lipids.
CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most...
-
Upload
jason-francis -
Category
Documents
-
view
242 -
download
5
Transcript of CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most...
![Page 1: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/1.jpg)
CHEM 3303.02 Biochemistry
Chapter 10:Lipids
![Page 2: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/2.jpg)
Knowledge/ skillsEntire chapter- All except for most of
Lipids as signals, cofactors and pigments
Storage lipids Structural lipids in membranes Vitamins A and D are hormone precursors Vitamins E and K and the lipid quinones are
oxidation/reduction cofactors
![Page 3: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/3.jpg)
General information Insoluble in water Principal energy storage ( fats and oils) Phospholipids and sterols are structural
elements of biological membranes Other as cofactors, electron carriers, light
absorbing pigments, hydrophobic anchors for proteins
Chaperones for membrane folding Emulsifying agents in digestion Many lipids play a passive role for energy
storage or as a barrier, some are active and play a role as messengers or signalling molecules such as hormones
![Page 4: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/4.jpg)
Storage lipids Fatty acids-
Complete oxidation to CO2 and H2O Carboxylic acids with hydrocarbon
chains ranging from 4-36 carbons Chain can be branched/unbranched Chain can be saturated/ unsaturated May contain ring structures
![Page 5: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/5.jpg)
naming Simplified
Chain length:number of double bonds Double bond position given by a Δ followed by
the number of the carbon which is participating in the double bond. Note that the carboxyl group carbon is C-1
E.g. 20:3(Δ3,9,12) denotes a carboxylic acid with 20 carbons and 3 double bonds between C-3 and C4; C-9 and C-10; C-12 and C-13
Most commonly occurring have even numbers with unbranched chains- results from the fact that in biological systems the chains are put together from two Carbon (acetate) units
![Page 6: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/6.jpg)
Many double bonds are Δ9, 12,15 in the cis configuration
Almost never see alternating single and double bonds but separated by a methylene group
Trans fatty acids produced by fermentation in diary animals and hydrogenation of fish or vegetable oils- these increase the levels of LDL or bad cholesterol and decrease the levels of HDL or good cholesterol
![Page 7: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/7.jpg)
![Page 8: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/8.jpg)
![Page 9: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/9.jpg)
Physical properties – solubility in water Largely determined by chain length and degree
of saturation of the hydrocarbon chain Longer fatty acyl chain- less soluble Fewer double bonds- less soluble Compare the solubility of lauric acid (12:0,
Mr200) 0.063mg/ml vs glucose (Mr 180) 1,100 mg/ml
Carboxylic acid group is polar and ionized at pH7 and accounts for the slight solubility of the shorter chain fatty acids in water.
![Page 10: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/10.jpg)
Physical properties- melting point
Influenced by length and degree of unsaturation of the hydrocarbon chain At room temp the saturated fatty acids from 12:0 to
24:0 are waxy while the corresponding unsaturated fatty acids are oily liquids
Differences due to the degree of packing of the molecules
In fully saturated molecules, large degree of free rotation around the C-C backbone and very flexible and able to pack tightly into nearly crystalline arrays with atoms in contact all along their length
Unsaturated- cis double bond forces a kink in the hydrocarbon chain- result is that cannot pack as tightly as the fully saturated form. Overall van der Waal’s interactions less in unsaturated so less thermal energy to break bonds hence have lower melting points
![Page 11: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/11.jpg)
![Page 12: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/12.jpg)
In vertebrates, free fatty acids with a free carboxylate group are bound to a protein carrier called serum albumin
Fatty acid derivatives such as esters or amides lack the charged carboxylate group and are less soluble than free fatty acids.
![Page 13: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/13.jpg)
Tri acyl glycerols
Composed of fatty acids linked to glycerol- by what linkage?
![Page 14: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/14.jpg)
Ester linkage due to formation of a condensation bond
Simple if all acids are the same, e.g. tristerin
Most are mixed
Polar groups of both glycerol and fatty acid are linked so triacylglycerols are nonpolar, hydrophobic and insoluble
Lower specific gravity- float on water
![Page 15: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/15.jpg)
Triacylglycerol function Energy storage in adipocytes as fat droplets Oils in plant seeds to provide energy and precursor
molecules for germination The carbon atoms of fatty acids are more reduced than
carbohydrates so that more than twice the energy (gram for gram) is yielded
Because the molecule is hydrophobic, do not need water of hydration associated with polysaccharides (2g per gram of polysaccharide)
Carbohydrates are a quick energy source and are readily soluble in water
Fats are better for long term storage Fats are good insulators against cold temperatures
especially in animals that live in the cold or hibernate Help with maintaining neutral buoyancy in diving
animals like whales
![Page 16: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/16.jpg)
There are 4 adipocytes in this picture
Can you tell where they are? Storage lipids can make up more than 80% of the
adipocyte dry cell mass
![Page 17: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/17.jpg)
The sperm whale Sperm whale’s head accounts for over 1/3 of its
body weight. About 90% made up of spermaceti organ that is filled with spermaceti oil. The oil helps the animal maintain neutral buoyancy at ocean depths where it hunts its food and is able to change density depending on temperature
![Page 18: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/18.jpg)
Saturation of oils Many vegetable oils such as corn and olive oil
are composed of triacylglycerols with unsaturated fatty acids- liquid at room temp
Hydrogenation reduces some double bonds to single bonds and can give trans double bonds
Exposure of lipids to air results in oxidative cleavage of double bonds to produce aldehydes and shorter chain carboxylic acids that are more volatile and smell rancid
![Page 19: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/19.jpg)
![Page 20: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/20.jpg)
Waxes Esters of long chain (C14 to C36) saturated and
unsaturated fatty acids with long chain alcohols
Melting points (60ºC – 100ºC) Can be used as a metabolic fuel store Provide water repellent properties- help to waterproof Lubricate hair and skin Protect against parasites E.g. lanolin, beeswax, carnuba wax
![Page 21: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/21.jpg)
![Page 22: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/22.jpg)
Lipid types
This is an important overall picture of the lipids and how they are built
![Page 23: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/23.jpg)
Lipids in membranes Membranes serve as a barrier to passage of
polar molecules and ions The molecules are amphipathic, one end is
hydrophobic and the other is hydrophilic The hydrophilic end interact with water on
either side of the membrane- can be a single OH or more complex as in the phospholipids, or sugars as in the glycolipids
The hydrophobic end interact with each other in a bilipid layer structure
Membrane lipids can make up 5 to 10% of the dry mass of cells
![Page 24: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/24.jpg)
Glycerophospholipid Aka phosphoglyceraldehydes
Two fatty acids attached via ester linkage to C-1 and C-2 of glycerol
Polar or charged group attached via a phosphodiester linkage to C-3 with an alcohol
Di acyl-glycerol
![Page 25: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/25.jpg)
Head group substituents
![Page 26: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/26.jpg)
![Page 27: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/27.jpg)
Ether lipids Alkyl ether lipid- saturated Plasmalogen- double bond between C-1 and C-2
![Page 28: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/28.jpg)
An example of ester and ether linkage Molecular signal to stimulate platelet
aggregation
![Page 29: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/29.jpg)
Galactolipids One or two galactose residues connected by
a glycosidic linkage to C-3 of a 1,2 diacylglycerol
Important in plant thylakoid membranes.
![Page 30: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/30.jpg)
![Page 31: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/31.jpg)
Sulfolipids Sulfonate group bears a negative charge
like a phosphate group
![Page 32: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/32.jpg)
Glycerol dialkyl glycerol tetraether
Found in archaebacteria- live in extreme conditions of pH and temperature
Molecule is longer (32C) to make a membrane with a hydrophobic core and hydrophilic ends (glycerol)
Ether bond linkage more stable to hydrolysis than ester bond
![Page 33: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/33.jpg)
Sphingolipids Polar head group but use the long chain amino
alcohol sphingosine instead of glycerol Has one long chain fatty acid Has a polar head group linked by a glycosidic
linkage or phosphodiester linkage
![Page 34: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/34.jpg)
![Page 35: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/35.jpg)
![Page 36: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/36.jpg)
![Page 37: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/37.jpg)
Breakdown of membrane lipids
Membrane lipids continuously made/broken
Specific enzymes attack each hydrolyzable bond
Defects in these enzymes lead to severe consequences (Tay-Sachs)
![Page 38: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/38.jpg)
Diseases associated with problems in breaking down sphingolipids
![Page 39: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/39.jpg)
Sterols- e.g cholesterol Have 4 fused Carbon
rings, three 6 carbon and one 5 carbon to form the steroid nucleus- rigid and planar
Present in eukaryotic cells
Cholesterol is ampiphatic
Are precursors for steroid hormones which regulate gene expression
![Page 40: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/40.jpg)
Examples of sex hormones
![Page 41: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/41.jpg)
Vitamin A, D, E and K Fat soluble vitamins All are isoprenoid compounds synthesized
by condensation of multiple isoprene units Vitamin A and D are hormone precursors
![Page 42: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/42.jpg)
1,25-dihydroxycholecalciferol- a hormone that regulates calcium uptake in the intestine and Ca levels in kidney and bone; regulates gene expression to turn on synthesis of Ca 2+ binding protein
![Page 43: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/43.jpg)
![Page 44: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/44.jpg)
Vitamin A (retinol), hormone and visual pigment
![Page 45: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/45.jpg)
Vitamin E- collective name for tocopherols Contain a substituted aromatic ring and long
isoprenoid side chain. Are hydrophobic and associate with
membranes, lipid deposits and lipoproteins Aromatic ring destroys free radicals to protect
fatty acids from being oxidized
![Page 46: CHEM 3303.02 Biochemistry Chapter 10: Lipids. Knowledge/ skills Entire chapter- All except for most of Lipids as signals, cofactors and pigments Storage.](https://reader035.fdocuments.net/reader035/viewer/2022062308/56649e735503460f94b7387b/html5/thumbnails/46.jpg)
Vitamin K Undergoes oxidation and reduction during
active prothrombin formation. Prothrombin splits the peptide bonds in
fibrinogen to fibrin an insoluble protein that holds blood clots together