10 Nebal Al - Gallab Shatha Al - Jabri Mamoon Ahram
Note: the doctor showed extra examples, they were in the slides, you can refer to them... Naming of Fatty Acids - 1 st Method ( IUPAC system ) We start counting from C (carboxylic carbon/functional group) as number 1. Ex. If we have a chain of fatty acids that contain 18 C 18 C=8 C+10 C Octa + deca = OctaDecan (Alkane) +COOH Okay. If we have double bond: OctaDecanoic Acid Convert OctaDecanoic OctaDecenoic (1 Double bond) OctaDecaDienoic (2 Double bond) OctaDecaTrienoic (3 Double bond) Designation of Fatty Acid - Number of Carbon & Bond - Location of bonds 18 : 0 n Δ : position of double bond 18 : 1 18 Carbons & 1 double bond 9 Ex. : cis-δ : cis double bond between C 9 and 10 1 P a g e
2 Trans-Δ : a Trans double bond between C 2 and 3 *We can also specify double bond Cis or Trans. Slides 12+13 in Lipids: important Fatty Acid you should memorize. 2 P a g e
-2 nd Method (street way of naming) Omega System (ω) : Omega, last letter in Greek alphabet. We start counting from C (methyl) away from carboxylic group COOH -Omega 3 means that double bond located between C3 & C4 when we start from the distal C (Methyl). *Ex. 18 : 3 Δ9,12,15 position of double bonds Omega 3 Linolenic acid Number of C Number of double bonds 3 P a g e
*In omega system, we don t know number of double bonds & Carbons in the chain because we don t talk about single fatty acid; we talk about Class of Fatty Acids that share the position of First double bond relative to C-Methyl. *Derivatives of Fatty Acids Molecules derived from fatty acids (Linoleic, Arachidonic...) -Eicosanoid : Molecules derived from Fatty Acids which contain 20 C atoms OR Class of molecules derived from Arachidonate (20 C - 4 double bond), Eico : 20 *From Arachidonate, we have 4 types of Eicosanoid: -LeukoTrienes; refers to leukocytes (immune cells), Tri: 3, ens: double bonds. -Prostacyclins; its source is from Prostate gland & looks like Cyclic. -Prostaglandins; synthesize from Prostate gland. -Thromboxanes; high level in blood. But, Are these molecules found only in these cells? No, it may found in another type, but the first time they were discovered in these cells. 4 P a g e
*Functio ns of Eicosanoid s Platelet aggregation Inhibition Activation prostaglandins Prostacyclins/ Vasodilator Thromboxanes Constriction of Smooth muscles Thromboxanes leukotrienes/leads to Asthma They have contradictory functions, that doesn t mean they stop each other s functions or work at the same time, there is homeostasis, it starts as vasodilator then becomes vasoconstrictor to reach homeostasis. *Note: Leukotrienes constrict smooth muscles of blood vessels & causes constriction of bronchus so reduce blood flow & may cause Asthma. *Aspirin Miraculous Molecule Works as inhibitor for Enzyme (Cyclooxygenase) which converts Arachidonic Acid to prostaglandins. Recommended to take baby- Aspirin frequently in small amounts to reduce rate of heart attack (protection) especially for elderly people. 5 P a g e
Why? Because they found that aspirin targets enzyme called cyclooxygenase; which converts Arachidonic Acid into prostaglandins, which reduces blood aggregation, so it prevents blood clotting. When a doctor describes Aspirin for a patient, he should ask him if he has a problem in his stomach, why? Because Cyclooxygenase is Not a single enzyme, it s a class of enzymes (COX-1, COX2,) that is found in different tissues, so the problem is that Aspirin inhibits all types of it. *Note: COX-1 COX-2 important in Homeostasis (that s why it causes problems in stomach) responsible of inflammation SO... Scientists discover better drug Celebrex inhibits COX-2 only. *Celebrex act as : -Antiplatelet -Anti-inflammatory Celebrex Reduces temperature, pain BUT when Aspirin went down on the markets in America, the doctors withdrew it because they believe that Aspirin causes problems for people who suffer from heart problems but later on, they found that people who already have problems in their heart shouldn t take this drug. 6 P a g e
*Notes from lecture : ** Omega-3 which is the Precursor for EPA + DHL is very useful for us; it is involved in the membrane of neurons in our brain so it Promotes Memory. -Food that contain Omega-3: Nut, Almonds, Sardine, and Tuna... **Omega-6 comes from Arachidonic Acid. **Omega-9 : -Reduces cholesterol; Mediterranean people have lower rate of heart attack because their food depends mainly on Olive Oil, also Iskimo people have a good physical structure because it s food (fish) contains Omega-3 very useful. 7 P a g e
Complex Lipids *You should know for each Fatty Acid it s Backbone And the structures that connect to it, For instance TAG : it s backbone Glycerol with 3 Fatty Acids connected to it, stored mainly in adipose tissue so when your body needs energy, a signal is sent to release Fatty Acids to blood then to another tissue. *In TAG, we have Glycerol molecule (3 OH group) + Fatty Acids. -Reactions between OH and COOH form Ester linkage. -Simple TAG... 3 Same Fatty Acids -Complex TAG... 3 Mixed Fatty Acids -What s the importance of the type of F.A that connects to Glycerol? Promotes physical properties for tri-glyceride itself. 8 P a g e
-shape of saturated F.A >> Chain -F.A has Cis double bond >> has kink So when a TG has 3 chains of saturated F.A >>will become Packed> hydrophobic interaction between them Forms FAT -Unsaturated F.A (F.A is Cis double bond)>>will become near each other, repulsion happens >>so the shape of TG differs, so more fluidic form of Oil **Saponification soap production We separate the F.A from TG by Alkaline hydrolysis >>F.A + Salts become together >>How does the soap work? -Carboxyl group (Head) hydrophilic on surface -Inside the tail which is hydrophobic >with water. The F.A will be released, tail hate the water so will aggregate each other forming Micelles. -Grease + Dirt are Hydrophobic so they become entrapped inside micelles. **Hydrogenation Removal of double bond when adding Hydrogen yields Saturated F.A >convert from Oil to solid F.A. elimination of double bond by hydrogenation. 9 P a g e
- It s important in industry because it can produce Trans-Fat from Cis bond, forms kink. *when we have Cis-Fat: 1-If we have complete hydrogenation > will produce saturated F.A (No benefit) 2-If we have partial hydrogenation > will convert the Cis to Trans (appears as saturated) - Advantages of 2 nd way: it s taste delicious, long sheilf life so it take long time to spoil Disadvantage of 2 nd way: a) Our body can t deal with Trans, Only with Cis, because Trans can t be digested. b) Tends to aggregate to form blood clot, so closed blood vessels, so more prone to heart diseases (Coronary Heart Disease). It s used because the half-life of it is longer and it tastes better. -Margarine 10 P a g e
In margarine, only about two-thirds of the double bonds present in the starting vegetable oil are hydrogenated, so that the margarine remains soft in the refrigerator and melt on warm toast. **Waxes : -Combination of 2 things (F.A + long chain Alcohol) -When linked together they form Ester linkage -Overall it s Solid -we can t Digest Wax > don t have Enzyme that digest Wax in our body, it has a long halflife. **Membrane Lipids -the most prevalent lipid in membrane is Glycerophospholipid. 11 P a g e
**Phospholipids: -Simplest type >(Phosphatidic acid- most abundant) /has Glycerol + F.A + phosphate *instead of phosphate we can put another groups yields to another types. **Cephalins -Phosphatidylethanolamine -Phosphatidylserine -abundant in brain *Inositol: sugar molecule, signalling molecule (sends messages across cell membranes) *Choline: Snake venom contain lecithinase, which hydrolyses polyunsaturated fatty acids and converting lecithin into lysolecithin, eventually cause hemolysis of RBCs. 12 P a g e
**Emulsification -F.A important in Emulsification which is important in Industry > Resolving Fatty problem in the Hydrophilic environment -When we eat ice-cream, mayonnaise > they contain F.A but incomplete because of Emulsification. -Emulsifying agent : is substances that can surround nonpolar molecules and keep them in suspension in water. -Because of lecithin s amphipathic nature, they act as emulsifying agents. Allah would never place you in a situation That you can t handle 13 P a g e
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