1. PRINCIPLES OF BIOCHEMISTRY
BCM 3000
PRINCIPLES OF BIOCHEMISTRY
(Semester /12)

2. LIPID Learning outcome (Objectives) Function and distribution.
Characteristics of fatty acids-structure and chemical properties.
Saturated and unsaturated fatty acids .
Structures and properties of phospholipids, sphingolipids, waxes, terpenes and steroids.

6. ???????

7. LIPID Fat : Triglycerides in the form of solids at room temperature
DEFINITION : General definition – all compounds called fat and oils
TECHNICAL DEFINITION
Fat : Triglycerides in the form of solids at room temperature
Oils : Triglycerides which are liquid at room temperature

8. General Definition
Any natural compound which is insoluble or nearly insoluble in water but soluble in non-polar solvents –
Chloroform
CS2
Ether
warm or
hot ethanol

9. FUNCTIONS
Lipids are widely distributed in both animal and plant systems and perform a wide variety of functions
Structural functions - Components of membranes
Storage forms of carbon and energy
precursor for major compounds – e.g. hormones.
Insulators - thermal, electrical or physical shock
protective coatings – prevent infections, loss or addition of compounds
Regulators - as vitamins & hormones

10. CLASSIFICATION 1. SIMPLE LIPIDS Fatty acid esters
(Acid + alcohol  ester)
2. COMPPOUND LIPID
Fatty acid + alcohol + OTHER COMPOUNDS

11. LIPID COMPONENTS SIMPLE LIPIDS
Acyglycerols
(Glycerol + Fatty acids) =
Waxes
Alcohol + fatty acids
SIMPLE LIPIDS
???
Esters

12. COMPOUND LIPIDS 4 types of Compound lipid i. Phosphoglycerides
ii. Sphingolipids
iii. Cerebrosides
iv. Gangliosides

13. LIPID COMPONENTS COMPOUND LIPID i Phosphoglycerides
Glycerol + Fatty acid HPO42- + satu OHR ii
Sphingolipids
Sphingosine + Fatty acid + HPO42- + Choline
iii
Cerebrosides
Sphingosine +Fatty acid + Simple sugar iv
Gangliosides
Sphingosine + Fatty acid+ 2-6 Simple sugar (Including sialic acid)
COMPOUND LIPID

14. i & ii = Phospholipid - presence of phosphate
ii , iii & iv = Sphingolipids - presence of Sphingosine
iii & iv = glycolipid - presence of carbohydrate

15. GLYCEROL –
Trihydroxy alcohol

17. FATTY ACIDS
Long chain aliphatic carboxylic acids- contains carboxyl group – polar head and `tail’ containing hydrocarbon chain
Amphiphilic compounds – hydrophilic head and hydrophobic tail
COOH can be ionised
Monocarboxyilic acids – linear hydrocarbon chain, even carbon numbers – between C12-C20
Short, longer , branched, cyclic and odd numbers also exist BUT not many

18. Octadenic acid

19. FATTY ACIDS
2 TYPES
Saturated Fatty acids
Unsaturated Fatty acids

20. Structure of Fatty Acids - Saturated
Fats
mostly from animal sources,
have all single bonds between the carbons in their fatty acid tails, thus all the carbons are also bonded to the maximum number of hydrogens possible.
saturated fats
The hydrocarbon chains in these fatty acids are, thus, fairly straight and can pack closely together, making these fats solid at room temperature.

21. Saturated fatty acid –e.g.
palmitic acid (CH3(CH2)14COOH) (16C) &
Stearic acid (CH3(CH2)16COOH)

22. Saturated Fatty Acids

23. Structure of Fatty Acids - Unsaturated
Unsaturation normally at - C18 & C20 – double bond separated by methylene group
-CH = CH - CH2 - CH = CH
Double bonds = cis configuration
Unsaturated fatty acid - oleic (18:1), Linoleic (18:2), Linolenic (18:3) & arachidonic (18:4)

24. Unsaturated fatty acids
C=C double bond arranged in two ways
In cis bonds, the two pieces of the carbon chain on either side of the double bond are either both “up” or both “down,” such that both are on the same side of the molecule
In trans bonds, the two pieces of the molecule are on opposite sides of the double bond, that is, one “up” and one “down” across from each other
Naturally-occurring unsaturated vegetable oils have almost all cis bonds, but using oil for frying causes some of the cis bonds to convert to trans bonds

25. CIS
TRANS

27. Unsaturated Fatty Acids

28. fatty acids with trans bonds are carcinogenic, or cancer-causing.
containing products such as margarine are quite high,

29. Oils mostly from plant sources,
have some double bonds between some of the carbons in the hydrocarbon tail, causing bends or “kinks” in the shape of the molecules.
Because some of the carbons share double bonds, they’re not bonded to as many hydrogens
oils are called unsaturated fats.
kinks unsaturated fats can’t pack as closely together, making them liquid at room temperature

30. TRANS
CIS

32. Making margarine
Vegetable oils often contain high proportions of polyunsaturated and mono-unsaturated fats (oils)  liquids at room temperature.
You can "harden" (raise the melting point of) the oil by hydrogenating it in the presence of a nickel catalyst.

35. SIMPLE LIPIDS 2 GROUPS Neutral acyglycerols (e.g. Triacylglycerol)
Waxes
Acyglycerols
= glyceride = a tryhydroxy alcohol ester
= glycerol + fatty acid (3 different fatty acids)
= can be esterified

36. Glycerol = trihydroxy
alcohol

37. TRIACYGLYCEROLS

42. Triacylglycerol – the most abundant
No ionic groups -  neutral lipids
Triacylglycerol = neutral fats neutral oils (liquid)

43. FUNCTIONS IN ANIMALS
Adipose tissues - `fat depots' = storage forms of carbon and energy
II. Transport - chylomicrons - = lipoprotein – fatty acids are transported through lymphatic system and blood  tissue adipose tissues and other organs
III. `Physical protection' - e.g. temperature.

45. 

47. WAXES
Also an ester - alcohol & fatty acid = very long hydrocarbon chain – commercial application
hairs, skin, leaves, fruits

48. WAXES
Asid Oleic

49. CHEMICAL CHARACTERISTICS OF TRYACYLGLYCEROL (Reactions of Triacylglycerol)
1. Hydrogenation

50. HYDROGENATION PROCESS
Double bonds in vegetable oils can be hydrogenated  oils become solids – can control - e.g.. peanut butter - crunchy, creamy
HYDROGENATION PROCESS

51. 2. Halogenation – Addition of halogens
Other halides - Iodine(I2), Chlorides (Cl2)

52. Saturated fatty acid – iodine number = 0
Oleic acid - 90,
linoleic- 181,
Linolenic = 274

53. Animal fat-iodine number is low
Vegetable oils – iodine number is high

55. Base Hydrolysis = SAPONIFICATION
(i.) Base Hydrolysis  Fatty acid + Glycerol or Salts of fatty acid + Glycerol
inside cells – by enzymes (lipase) – very specific for ester bonds – products are glycerol + fatty acids
Non-enzymatic- with alkali (base)  salts of fatty acid + Glycerol
salts of fatty acids = soap
Base Hydrolysis = SAPONIFICATION

56. SAPONIFICATION
The reaction of triacylglycerol with base (alkali) - e.g.. NaOH, KOH
Triacylglycerol – presence of strong ester bond
Ester bond can be hydrolyzed by base  salts of fatty acid + glycerol
Salts = soap – react as a soap/detergent

57. Saponification reaction
(Base Hydrolysis)

58. If R= palmitic acid  Sodium palmitate
If R’= oleic acid  Sodium oleate
R”= stearic acid  Sodium stearate

60. Detergent? =`surface active agents' – lower surface tension of surface of water
H2O = `poor cleansing agent - Y?  Because the molecule is very polar and tend to stick to each other – therefore cannot enter non-polar areas like grease, oil, dirt

61. HOW DOES A DETERGENT WORK ??
Hydrophobic tails enters grease layers
ii. Hydrophilic heads come into contact with aqueous layer  separate grease layer from the surface
Small grease globules form- `pincushion‘
These globules have similar charges - therefore cannot go near each other – can wash

62. Water
Grease

65. Best detergent strong hydrophilic and hydrophobic tail
Ordinary soap = mixture of potassium salts of fatty acids from saponification - not a very good detergent ? e.g. Sodium palmitate
The negative ions in soap forms precipitate with metals in hard water (?)  use syndets = soluble in water
e.g.. SDS = Sodium dodecil sulfate

66. Head -
Polar
(hidrofilik)
Ekor-
Tak polar
(Hidrofobik)

67. (ii). Acid Hydrolysis
Carboxylic acids

68. 4. RANCIDITY
Expose triacylglycerol to warm and moist air  rancid (tengik)
2 reactions take place
Ester hydrolysis
Oxidation of the double bonds
Hydrolysis - water (inside the lipid) + enzyme (bacteria in the air)
Oxidation-by O2 on the side chain of triacylglycerol  short chain fatty acids – rancid (tengik)

70. Phosphoglycerides Phosphoglycerides = Phosphoglycerol
i.e. they are derived from glycerol
Fatty acids
Glycerol
Phosphate group

71. Phosphoglycerol = Phosphoglyceride
other alcohols
Phosphoglycerol = Phosphoglyceride

72. Glycerol (Trihydroxyglycerol)
Phosphatidic acid
(Glycerol + 2 fatty acids + Phosphate)
Phosphoglyceride (Phosphoglycerol)
(Glycerol + 2 fatty acids + Phosphate + other
group e.g.. alcohol)

73. All phosphoglycerides are Phospholipids!!!!

74. Phosphoglycerides can be further esterified to form  other lipids
Phosphatidylcholine ( choline ester)
Phosphatidylethanolamine (ethanolamine)
Phosphatidylserine (serine)
 All are important components of membranes

75. Asid lemak
Phosphate

76. Phosphatidylethanolamine

77. Phosphatidylethanolamine

78. Phosphatidylserine

79. Membrane

80. SPHINGOLIPID No glycerol – replaced with amine alcohol = Sphingosine
Number of carbon atoms –varies
The simplest = ceramides = Fatty acid + sphingosine through amino group via amide bond
Sphingomyelin – an example of sphingolipid - 1o alcohol esterified to phosphate
 amino alcohol (= choline)
Found in nerve membranes and brain

81. SPHINGOLIPID CHCH(CH2)12CH3  H2C OH CHOH  H2COH CH NH2 CH2OH
What is the main structure for sphingolipid?
Sphingosine
Draw the structure of sphingosine
Draw the structure of glycerol and compare between the two
CHCH(CH2)12CH3 
CHOH
CH NH2
CH2OH
H2C OH 
H2COH
Sphingosine
Glycerol

82. SPHINGOLIPID No glycerol – replaced with amine alcohol = Sphingosine
Number of carbon atoms –varies
The simplest = ceramides = Fatty acid + sphingosine through amino group via amide bond
Sphingomyelin – an example of sphingolipid - 1o alcohol esterified to phosphate
 amino alcohol (= choline)
Found in nerve membranes and brain

83. CERAMIDE

84. Phosphate
Choline

85. GLYCOLIPID When a carbohydrate is attached to OH- via glycosidic bond
Seb. induk = ceramide (sphingolipid) + CHO
Cerebroside - CHO = glucose @ galactose
 glucocerebroside
GANGLIOSIDE – ALSO contains oligosaccharide + sialic acid

87. DERIVED LIPIDS A heterogeneous group Derived from fatty acids
steroids, prostaglandin, leukotriene, carotenoids, vitamin
STEROID
All organisms – similar basic structure – fused ring= perhydrocylopentanophenanthrene

90. STEROL Hydrocarbon chain (C18-C20) at C17
ii. Hydroxyl group (OH) at C3
Main example = CHOLESTEROL – structural component of membrane % lipid membrane. Rigid
Precursor of bile, sex hormones, vit. D.
Role in atherosclerosis

91. Hydrocarbon chain at C17
OH at C3
CHOLESTEROL

93. TERPENE Lipid derived from isoprene
Term used for all compounds synthesized from the precursor isoprene  cholesterol, bile acid, steroid, lipid soluble vitamins = terpene
Oils from turpentine (pine tree extracts)
formula C10H15
> 15 carbon atom also found - `multiples of 5
Also in other plants

94. TERPENE EXAMPLES: Terpene with 20 carbon atoms - vit. A
- 40 carbon atoms - b- carotene
EXAMPLES:
monoterpene - Limonene - `odor' lemon
Diterpene - Gibberrelic acid – plant hormone
Triterpene - Squalene – Cholesterol precursor
Tetraterpene - Lycopene - tomato pigments

95. TERPENE

96. TERPENE

97. TERPENE

98. PRINCIPLES OF BIOCHEMISTRY
BCM 3000
PRINCIPLES OF BIOCHEMISTRY
(Semester /12)

99. LIPID BEHAVIOUR IN WATER
Lipid – not soluble in water but can still be found in aqueous environment
behavior in water important to understand the phenomena
A lot of lipids are amphiphyllic = having
hydrophobic part (hydrocarbon chain)
polar (ionic) part

100. When lipid is dispersed in water, the hydrophobic part will segregate from the solvent through `self-aggregation' – form
micelles – which are dispersed in water
monolayers ( aggregate – boundary H2O: air

101. MONOLAYER
MICELLES

102. The tendency for hydrocarbon chains to distance away from polar solvents gives rise to = HYDROPHOBIC EFFECT
Most lipids will form micelles – spheres, ellipse, discs, cylinders
Also can form vesicles – bilayer – hydrocarbon chains are opposite to each other  `hollow sphere'

103. Micelle
Bilayer
Vesicles

104. BILAYER

105. Cholesterol does not form micelles ??
Not amphiphatic compounds
Structure – flat fused ring -  solid –difficult to form micelles
Can form mixed micelle with amphiphatic lipids mixed micelles – with amphiphatic lipids

106. BILE ACID AND BILE SALTS
Bile acids serve many functions.
They aid in fat absorption
Bile acids are produced from cholesterol in the liver.
Cholesterol is converted to the carboxylic acids cholic and chenodeoxycholic acid, which are the primary bile acids in most species.
The liver conjugates the acids to either glycine or taurine and subsequently secrets them into the bile.
The gall bladder serves to store bile acids until contraction associated with feeding

107. Glycine
Taurine

108. LIPOPROTEIN STRUCTURE Particles that contain lipid and protein
bonds = not (non-covalent) bonds
Function – In blood plasma – to transport triacylglycerol and cholesterol
STRUCTURE
- form `micelle like particles' -
i. core – non-polar triacylglycerol
ii. Surrounded by a layer of amphiphilic protein, phospholipid and cholesterol

109. Various categories – depending on the functions
CHYLOMICRON – Carries exogenous triacylglycerols & cholesterol (from diet) from intestine to the tissues.
LDL, IDL & LDL – group of related particles which carry endogenous triacylglycerols & cholesterol (produced internally) from the liver to tissues
NB: liver can synthesize triacylglycerol from excess carbohydrate

110. CHYLOMICRON

112. LDL, CHOLESTEROL & ATHEROSCLEROSIS
Important component of membrane – can be supplied from the outside or internally (if not enough)
How obtained externally ? – ENDOCYTOSIS – Through reaction of specific receptors = LDL receptor?
protein part of LDL tie up to R-LDL in the cell complex  `pinched off' = endocytosis

113. ENDOCYTOSIS vs EXOCYTOSIS

115. HDL Oversupply ? – Protein – recycled – used in the cell
Synthesis of R-LDL inhibited  low LDL  cholesterol level in blood increases  deposited in the artery  heart disease; stroke
HDL
Function opposite of LDL
Carries cholesterol from tissues - extract cholesterol from membrane – change to `cholesteryl esters - LCAT (Lecithin cholesterol transferase)  bile acids