Upload
dennis-valdez
View
217
Download
0
Embed Size (px)
Citation preview
7/28/2019 Biochem Lec s IV. Lipids
1/14
CHAPTER IV: LIPIDS
DESCRIPTION Gk., lipos, Structurally heterogeneous group of substances of biological origin that are soluble in organic solvents,
but not in water Either
o Hydrophobico Amphipathic
FUNCTIONS1. Energy Source2. Energy reserve3. Insulation4. Protection5. Cell membrane structural components6. Chemical messengers in the human body.7. Vitamins8. Vitamin absorption
CLASSIFICATION ACCORDING TO SOLUBILITY IN NON-POLAR SOLVENTS:
FIGURE 1: Classification of Lipids According to Solubility in Non-polar Solvents
I. FATTY ACIDS Monocarboxylic acids that contain long, unbranched hydrocarbon chains generally 12-26 carbon atoms in
length Building blocks of all saponifiable lipids
o Lipids containing fatty acids: Waxes Fats and oils (triacylglycerols), Glycerophospholipids, Prostaglandins
o Lipids that do not contain fatty acids: steroids Melting point depends on both the length of their hydrocarbon chains and in the degree of unsaturation
(number of double bonds per molecule)
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER1 of 14
REVISION # 00
7/28/2019 Biochem Lec s IV. Lipids
2/14
A. SATURATED FATTY ACIDS Carbon-to-carbon chains are single bonds
NAME RATIO CONDENSED FORMULA RCOOH FORMULA SOURCESButyric CH3(CH2)2COOH C3H7COOHCaproic CH3(CH2)4COOH C5H11COOHCaprylic CH3(CH2)6COOH C7H15COOHCapric CH3(CH2)8COOH C9H19COOHLauric (Lt.,Laurus) CH3(CH2)10COOH C11H23COOHMyristic (Myristica, nutmeg genus) CH3(CH2)12COOH C13H27COOHPalmitic (Lt.,Palmitica, palm tree) CH3(CH2)14COOH C15H31COOH
Stearic (Gk., stear, hard fat) CH3(CH2)16COOH C17H35COOHArachidic (Lt., arachis, legume) CH3(CH2)18COOH C19H39COOH
TABLE 1: Saturated Fatty Acids
B. UNSATURATED FATTY ACIDS Carbon chains with one or more cisdouble C=C bonds as shown by the kinks in the fatty acid chains.
a. Monounsaturated fatty acids:NAME RATIO CONDENSED FORMULA RCOOH FORMULA SOURCES
Palmitoleic Acid CH3(CH2)5CH=CH(CH2)7COOH C16H31COOHOleic (Latin oleum, oil) CH3(CH2)7CH=CH(CH2)7COOH C16H29COOH
TABLE 2: Monounsaturated Fatty Acids
b. Polyunsaturated fatty acids Up to 6 double bonds are found in biologically important unsaturated fatty acids
NAME RATIO CONDENSED FORMULA RCOOH FORMULA SOURCESLinoleic Acid* CH3(CH2)4CH=CH(CH2)7COOH C16H31COOHLinolenic Acid* CH3CH2CH=CHCH2CH=
CHCH2CH=CH(CH2)7COOHC17H29COOH
Arachidonic Acid* CH3(CH2)4CH=CHCH2CH=CHCH2CH=CHCH2CH=CH (CH2)3COOH
C19H31COOH
Eicosapentanoic Acid(EPA)
CH3CH2 (CH=CHCH2)5(CH2)2COOH C19H29COOH
Docosahexanoic Acid(DHA)
TABLE 3: Polyunsaturated Fatty Acids
2 Families of Polyunsaturated Fatty Acids (Omega Classification)i. Omega-3 Fatty Acid
Polyunsaturated fatty acid with its endmost double bond three carbons away from itsmethyl end
Sourcesii. Omega-6 Fatty Acids
Polyunsaturated fatty acids with is endmost double bond six carbons away from itsmethyl end
Sources: ESSENTIAL FATTY ACIDS
o Fatty acids needed by the human body and must be obtained from dietary sources because theycannot be synthesized within the body from other substances
o Deficiency:o Linoleic acid, Linoeic acid, Arachidonic acid
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER2 of 14
REVISION # 00
7/28/2019 Biochem Lec s IV. Lipids
3/14
PROPERTY SATURATED FATTY ACID UNSATURATED FATTY ACIDChemical compositionChemical structureCC bonds within the chainChraacterisitic group of HCShape of HC chainPhysical State (RoomTemperature)Melting Point of same ChainLengthRelationship between MeltingPoint and Chain Length
TABLE 4: Similarities and Differences Between Saturated and Unsaturated Fatty Acids
II. GLYCEROL ESTERSA. TRIACYLGLYCEROL (TAG) or TRIGLYCERIDES or NEUTRAL GLYCERIDES
Compound formed by esterification of three fatty acids to glycerolo GLYCEROLo GLYCERIDES
Sources: adipose tissue, butterfat, cream, olive oil, cottonseed oil, corn oil, peanut oil, lard, bacon, suet,chicken fat, fish oil
Esterification:o Carboxylic acid + alcohol ester + water
Types:a. Simple fats/Glycerides
b. Mixed fats/Glycerides
FIGURE 2: Mixed Glyceride
FATS AND OILS Naturally occurring mixtures of tri-esters formed from the reaction between three (3) fatty acid molecules
and a glycerol molecule Formed when the hydroxyl groups of glycerol react with the carboxyl groups of fatty acids.
BASIS FATS OILSPhysical state at roomtemperatureSourceCompositionMelting point
TABLE 5: Differences between Fats and Oils
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER3 of 14
REVISION # 00
7/28/2019 Biochem Lec s IV. Lipids
4/14
PROPERTIES OF TRIACYLGLYCEROLS: Fats and Oils1. Physical properties
a.b.c.d.
2. Chemical propertiesa. GLYCERIDE FORMATION
FIGURE 5A: Formation of Glycerides
b. HYDROLYSIS Breaking down of ester linkages in the presence of catalyst (acid, base or enzyme)
H+ or enzymes+ 3 H2O 3 fatty acids +
FIGURE 6: Hydrolysis of Glycerides
c. SAPONIFICATION Hydrolysis reaction carried out in an alkaline/basic solution
d. CATALYTIC HYDROGENATION Double bonds in unsaturated fatty acids react with H2 in the presence of a Ni or Pt
catalyst heated at about 200C.
H HNi | |
CH = CH + H2 C C | |H H
FIGURE 7: Catalytic Hydrogenation of Tripalmitolean
e. RANCIDITYi. Hydrolytic rancidityii. Oxidative rancidity
Naturally occurring Synthetic
H2O, H+ H2, Ni
NaOH
FIGURE 8: Reaction Map for Triglycerides
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER4 of 14
REVISION # 00
Glycerol plus Fatty Acids Triglyceride A more saturatedtriglyceride
Glycerol plus Fatty Acid
7/28/2019 Biochem Lec s IV. Lipids
5/14
B. PHOSPHOLIPIDS/PHOSPHOACYLGLYCEROLS/GLYCEROPHOSPHOLIPIDS Triester of glycerols in which two OH groups are esterified with fatty acids and the third is esterified
with phosphoric acid, which in turn is esterified to an alcohol
FIGURE 9: General Structures of Phospholipids
FIGURE 10: Structures of Different Phosphoacylglyceride
PHOSPHOLIPID NAME OF X FORMULA OF X
Phosphatidic acid
Phosphatidylethanolamine Ethanolamine
Phosphatidylcholine Choline
Phosphatidylserine Serine
Phosphatidylglycerol Glycerol
TABLE 6: Prosthetic Groups for Phosphoacylglyceride
1. Phosphatidylcholines:o Amino alcohol:o Waxy solids that form colloidal suspensions in watero Sources: egg yolks and soy beanso Synthesized by the livero Functions
Component of cell membrane Nutritive supplement: improves memory Emulsifiers: mayonnaise, ice cream and custards Aid in the transport and absorption of fatty acids
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER5 of 14
REVISION # 00
7/28/2019 Biochem Lec s IV. Lipids
6/14
2. PhosphatidylethanolaminesandPhosphatidylserines:o Amino alcohols:o Found in heart and liver tissue and in high concentrations in the braino Important in blood clotting
3. Plasmalogeno Ether linked alkenyl chaino Brain, heart, muscle
III. NON-GLYCERIDE ESTERSA. WAXES Everyday Definition: Chemical Definition: Esters of saturated fatty acids and long-chain alcohols other than glycerol Uses: protective coatings, used in manufacturing candles.
OC O
FIGURE 11: Structural Formula for Waxes
a. Beeswax from honeycomb; chiefly made up of myricyl palmitateb. Cerumenearwax;c. Spermacetifrom the skull of certain whales and dolphins; chiefly made up of cetyl palmitate; used
in candle makingd. Chinesewax found in the secretions of insectse. Carnaubawax found in the cuticle of leavesf. Jojoba wax base of ointments
TABLE 7: Some Typical Waxes
B. SPHINGOLIPIDS Contain a long-chain amino alcohol called sphingosine, rather than glycerol SPHINGOSINE CERAMIDES
FIGURE 10: General Structure of Sphingosine, Ceramide and Sphingolipids
a. Sphingomyelins Sphingolipids in which the esterifying group is phosphoric acid to which choline is
attached Found in all cell membranes
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER6 of 14
REVISION # 00
Long chain alcoholFatty Acid
Alcohol
7/28/2019 Biochem Lec s IV. Lipids
7/14
Important component of myelin sheath, the protective and insulating coating thatsurrounds the nerves.
Increases the speed of nerve impulse Contains sphingosine
TABLE 8: Types of Sphingomyelins
b. Glycolipids/Glycosphingolipidso Lipids containing a fatty acid, sphingosine, and carbohydrate
i. Glucocerebrosides/Cerebrosides Simplest of carbohydrate containing lipids Monosaccharide forms glycosidic bond with the OH of the ceramide Occur primarily in the brain (7% by dry mass) in myelin sheath of nerves Important in cellular recognition and tissue immunity
ii. Gangliosides More complex carbohydrate heads; up to seven monosaccharides bonded to ceramide Occur in gray matter of the brain as well as in the myelin sheath (i.e., brain, nerves,
spleen) Present in cell membranes where they act as receptors for hormones, viruses and certain
drugsiii. Galactosyl diglyceridesiv. Sulfolipids/Galactolipids
C. STEROIDS Lipids with structures based in a fused-ring system (steroid nucleus) involving three six-membred ring
and five-membered ring Steroid nucleus
o Cylopentanoperhydrophenanthrene (CPPP)o consists of 3 Cyclohexane rings + 1 Cyclopentane ringo No fatty acids
FIGURE 13: Chemical Structures of the Steroid Nucleus and Cholesterol
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER7 of 14
REVISION # 00
SPHINGOLIPID NAME OF X FORMULA OF XCeramide
Sphingomyelin Phosphocholine
GangliosideGM2
Complex oligosaccharide
***GalNac: N-Acetyl D-Galactosamine***Neu5Ac: N-acetylneuraminic acid (sialic acid)
Figure 12: General Structure of Glycolipids
7/28/2019 Biochem Lec s IV. Lipids
8/14
1. Cholesterolo Most abundant steroid in the human body which is synthesized in the livero Derived from squaleneo Found in cell membranes (up to 25% by mass), nerve tissue and brain tissue (about 10% by dry
mass), and is a main component of gallstoneso Considered elevated if plasma cholesterol exceeds 200 mg/dL.o Functions: starting material for the synthesis of numerous steroid hormones, vitamin D, and bile
saltso Sources: nerve tissue, bile, gall stones, spleen, kidney, brain, sweet breads, liver, egg yolk; whole
milk, butter, fish roe, cheese, ice cream, meats
2. Bile Saltso Emulsifying agents that make dietary lipids soluble in the aqueous environment in the digestive
tracto Product of cholesterol oxidationo Source is bile
3. Steroid Hormoneso ANABOLIC STEROIDS
Derivatives of testosterone Serious ADRs
Increase blood lipid levels very high risk for heart diseases Liver toxicity Male reproduction system alteration Female:
FIGURE 14: Chemical Structures of Some Anabolic Steroids
o HORMONES Produced from cholesterol Chemical messengers produced by ductless glands
o Classes of Steroids:a.Sex hormones
Controls reproduction and secondary sex characteristicsi. Estrogens
Female sex hormones, synthesized in the ovaries and adrenal cortex Example: Functions: Responsible for the development of female secondary characteristics at the onset of
puberty Regulation of menstrual cycle Stimulate development of mammary glands during pregnancy Induce estrus in animals
ii. Androgens Male sex hormones; synthesized in testes and adrenal cortex Example: Functions: Responsible for the development of male secondary characteristics Promote muscle growth
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER8 of 14
REVISION # 00
7/28/2019 Biochem Lec s IV. Lipids
9/14
iii. Progestins Pregnancy hormones; synthesized in ovaries and placenta Example: Functions Prepare lining of the uterus for the implantation of fertilized ovum Suppresses ovulation
b. Adrenocortical hormones Regulate numerous biochemical processes in the body Produced by adrenal glands located on the top of each kidney.
i. Mineralocorticoids Control the balance of Na+ and K+ ions in the body ALDOSTERONE
FIGURE 16: Chemical Structures of Adrenocortical Hormones with their Biological Effects
ii. Glucocorticoids Control glucose metabolism and counteract inflammation CORTISOL
Cortisone4. Eicosanoids
o Oxygenated derivatives of polyunsaturated 20-carbon fatty acidso Precursor:o Gk., eikoso Exert effects in the tissues where they are synthesized
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER9 of 14
REVISION # 00
FIGURE 15: Chemical Structures of Sex
Hormones with their Biological Effects
7/28/2019 Biochem Lec s IV. Lipids
10/14
o Physiological effects: The inflammatory response, a normal response to tissue damage The production of pain and fever The regulation of blood pressure The induction of blood clotting The control of reproduction functions, such as induction of labor The regulation of sleep/wake cycle
a. Prostaglandins (PG) 20-carbon fatty acid derivatives that contain a cyclopentane ring and oxygen-containing
functional groups PGE soluble in ether; with ketone group at C-9 PGF soluble in phosphate buffer,fosfat(Swedish); hydroxyl group
b. Thromboxanes (TX) 20-carbon fatty acid derivatives that contain a cyclic ether and oxygen-containing
functional groups Produced by blood platelets
c. Leukotrienes (LT) 20-carbon fatty acid derivatives that contain three conjugated double bonds and hydroxyl
groups Found in leukocytes (white blood cells)
FIGURE 17: Formation of Eicosanoids
5. Fat Soluble Vitamins (Vitamin chapter)
IV. COMPLEX LIPIDS1. Aminolipids/Lipoproteins Combined lipids with proteins and phospholipids. Soluble in water because the surface consists of polar lipids. Differ in density, composition, and function. Parts:
o Hydrophobic core o Hydrophilic surface-
Types:a.CHYLOMICRONS
b.VLDL (Very Low Density Lipoprotein)c.IDL ( Intermediate Density Lipoprotein)d.LDL (Low Density Lipoprotein)e.HDL (High Density Lipoprotein)
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER10 of 14
REVISION # 00
7/28/2019 Biochem Lec s IV. Lipids
11/14
FIGURE 20: Formation of Arterial Plaques
CLASSIFICATION OF LIPIDS ON THE BASIS OF COMPOSITION/STRUCTURE
FIGURE 21: Classification of Lipids According to Composition or Structure
1. Simple lipids:a. Triglycerides/Triacylglycerol (TAG)
i. Fats:ii. Oilsare
b. Ester of fatty acids and high MW alcohols other than glyceroli. Waxes
ii. Cholesterylestersiii. VitaminDandAesters
2. Complex lipids:a. Phospholipidsi. Glycerophospholipids/Phosphoglyceridesalcohol
Lecithins Cephalins Plasmalogen
ii. Sphingophospholipids/Phosphosphingosidesalcohol: Sphingomyelins
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER11 of 14
REVISION # 00
7/28/2019 Biochem Lec s IV. Lipids
12/14
b. Glycolipids/Glycosphingolipidsi. Glucocerebrosides
ii. Gangliosidesiii. Galactosyldiglyceridesiv. Sulfolipids/Galactolipids
c. Other complex lipidsi. Aminolipids/Lipoproteins
3. Precursor and derived lipids:a. Fatty acids
i. Saturatedfatty acidsii. Unsaturatedfatty acids
1. Monounsaturated2. Polyunsaturated
iii. Cyclicfattyacidsb. Alcohols
i. Glycerolii. Sterol
iii. Cholesteroliv. Ergosterolv. Calciferol
c. Sphingosine CLASSIFICATION ON THE BASIS OF SAPONIFICATION:
FIGURE 22: Classification of Lipids According to Saponification
CELL MEMBRANES Separate cellular contents from the external environment. Consist of a lipid bilayer made of two rows of phospholipids.
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER12 of 14
REVISION # 00
7/28/2019 Biochem Lec s IV. Lipids
13/14
FLUID MOSAIC MODEL OF CELL MEMBRANES Contains proteins, carbohydrates, and cholesterol. Other substances
o Cholesterolo Glycolipids on surfaceo Proteins embedded in bilayero Proteins on surfaceo Unsaturated fatty acids
o Have proteins and carbohydrates on the surface
FIGURE 23: Diagram of a Cell Membrane
The transport of substances through cell membranes involveso Diffusiono Facilitated transporto Active transport
FIGURE 24: Types of Cell Membrane Transport
DISORDERS OF LIPID METABOLISM (Lipidoses)1. Gaucher's Disease
Caused by a buildup of glucocerebrosides, a product of fat metabolism, in tissues. Most common among Ashkenazi (Eastern European) Jews Leads to an enlarged liver and spleen and a brownish pigmentation of the skin. Accumulation
o Eyeso Bone marrow
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER13 of 14
REVISION # 00
7/28/2019 Biochem Lec s IV. Lipids
14/14
2. Tay-Sachs Disease Caused by a buildup of gangliosides (GM2), products of fat metabolism, in the brain and spleen owing
to lack of the enzyme hexosaminidase A. Most common among families of Eastern European Jewish origin.
3. Fabry's Disease Caused by a buildup of glycolipid, a product of fat metabolism, in tissues. Causes skin growths, pain in the extremities, poor vision, recurrent episodes of fever, and kidney or
heart failure.
4. Niemann-Pick Disease Caused by a buildup of sphingomyelin or cholesterol in the brain, spleen and liver due to a deficiency
of sphingomyelinase The most severe forms tend to occur in Jewish people. The milder forms occur in all ethnic groups.
o Type Ao Type Bo Type C
DISEASE LIPID STORED TYPE ENZYME ABSENTFabrys Gal-gal-glucosylceramide Ganglioside galactosidase
Gauchers Glucosylceramide Cerebroside glucosidaseNiemann-Pick Sphingomyelin Sphingolipid Sphingomyelinase
Tay-Sachs GM2 Ganglioside Ganglioside Hexosaminidase A
TABLE 9: Summary of the Different Lipid Metabolism Disorders
BIOCHEMISTRYLECTURE
Lipids
DATE DEVELOPEDJanuary 2012
DOCUMENT NO.
DEVELOPED BY:Sunshine A. Tayaotao
ISSUED BY:Sunshine A. Tayaotao
PAGE NUMBER14 of 14
REVISION # 00