Biochemistry 2/e - Garrett & Grisham ADVANCED BICHEMICAL ENGINEERING Chapter Lipids Nguyen Van Tuyen Copyright © 1999 by Harcourt Brace & Company Biochemistry 2/e - Garrett & Grisham What is lipid ? Barriers to more polar molecules - low solubility in water >< high solubility in nonpolar solvents - metabolic energy storage Copyright © 1999 by Harcourt Brace & Company Biochemistry 2/e - Garrett & Grisham Outline • • • • • • • 8.1 Fatty Acids 8.2 Triacylglycerols 8.3 Glycerophospholipids 8.4 Sphingolipids 8.5 Waxes 8.6 Terpenes 8.7 Steroids Copyright © 1999 by Harcourt Brace & Company Biochemistry 2/e - Garrett & Grisham Classes of Lipids • • • • • • All biological lipids are amphipathic Fatty acids Triacylglycerols Glycerophospholipids Sphingolipids Waxes Isoprene-based lipids (including steroids) Copyright © 1999 by Harcourt Brace & Company Biochemistry 2/e - Garrett & Grisham 8.1 Fatty acids - Several number of carbon atoms (usually 14 to 24) Copyright © 1999 by Harcourt Brace & Company Biochemistry 2/e - Garrett & Grisham 8.1 Fatty acids • Saturated (all carbon–carbon bonds are single bonds) Copyright © 1999 by Harcourt Brace & Company Biochemistry 2/e - Garrett & Grisham Fatty acids - II • Unsaturated fatty acids (with one or more double bonds in the hydrocarbon chain; monounsaturated – polyunsaturated ) Copyright © 1999 by Harcourt Brace & Company Biochemistry 2/e - Garrett & Grisham Fatty acids - III saturation >< unsaturation - Unsaturated fatty acids are slightly more abundant in nature than saturated fatty acids, especially in higher plants - chains pack tightly and form more rigid, organized aggregates (i.e., membranes) - Unsaturated chains bend and pack in a less ordered way, with greater potential for motion Arachidonic acid Copyright © 1999 by Harcourt Brace & Company Biochemistry 2/e - Garrett & Grisham - several other modified fatty acids a cyclopropane ring a branched-chain fatty acid - Some fatty acids are synthesized by mammals’s diet – plant source (linoleic and γ –linolenic acids, ) Copyright © 1999 by Harcourt Brace & Company Biochemistry 2/e - Garrett & Grisham 8.2 Triacylglycerols (triglycerides) • A major energy source the principal neutral derivatives of glycerol for many organisms • Why? - Most reduced form of carbon in nature yield large amounts of energy in the oxidative reactions of metabolism (1 g of triacylglycerols 38 kJ of energy) - Their hydrophobic nature allows them to aggregate in highly anhydrous forms - Efficient packing Copyright © 1999 by Harcourt Brace & Company 10 Biochemistry 2/e - Garrett & Grisham 8.5 Waxes Esters of long-chain alcohols with longchain fatty acids a weakly polar head group - Fatty acids are usually saturated - The alcohols may be saturated or unsaturated and may include sterols, such as cholesterol Copyright © 1999 by Harcourt Brace & Company 30 Biochemistry 2/e - Garrett & Grisham 8.5 Waxes Esters of long-chain alcohols with longchain fatty acids • Highly insoluble (weakly polar nature of the ester group) • Animal skin and fur are wax-coated • Leaves and fruits of many plants – coat stem • Bird feathers Carnauba wax Copyright © 1999 by Harcourt Brace & Company spermaceti 31 Biochemistry 2/e - Garrett & Grisham 8.6 Terpenes Based on the isoprene structure - A monoterpene (C10) consists of two isoprene units, - a sesquiterpene (C15) consists of three isoprene units, - a diterpene (C20) has four isoprene units Copyright © 1999 by Harcourt Brace & Company 32 Biochemistry 2/e - Garrett & Grisham 8.6 Terpenes Based on the isoprene structure Copyright © 1999 by Harcourt Brace & Company 33 Biochemistry 2/e - Garrett & Grisham 8.6 Terpenes straight chain or cyclic molecules Copyright © 1999 by Harcourt Brace & Company 34 Biochemistry 2/e - Garrett & Grisham Copyright © 1999 by Harcourt Brace & Company 35 Biochemistry 2/e - Garrett & Grisham Dolichol phosphate is an initiation point for the synthesis of carbohydrate polymers in animals Copyright © 1999 by Harcourt Brace & Company 36 Biochemistry 2/e - Garrett & Grisham Coumarin or Warfarin—Agent of Life or Death - to mg/day, prevents the deleterious formation in the bloodstream of small blood clots and thus reduces the risk of heart attacks much larger doses, cause massive hemorrhages and death Copyright © 1999 by Harcourt Brace & Company 37 Biochemistry 2/e - Garrett & Grisham 8.7 Steroids • Are complex derivatives of triterpenes • Based on a core structure consisting of three 6-membered rings and one 5-membered ring, all fused together • Found in all eukaryotes and small number of bacteria Copyright © 1999 by Harcourt Brace & Company 38 Biochemistry 2/e - Garrett & Grisham Cholesterol Cholesterol is the most common steroid in animals and precursor for all other steroids in animals Copyright © 1999 by Harcourt Brace & Company 39 Biochemistry 2/e - Garrett & Grisham Cholesterol - Rigid fused ring system of cholesterol and the weakly polar alcohol group at the C-3 position a principal component of animal cell plasma membranes - a component of lipoprotein complexes in the blood - one of the constituents of plaques that form on arterial walls in atherosclerosis Copyright © 1999 by Harcourt Brace & Company 40 Biochemistry 2/e - Garrett & Grisham Steroid Hormones Steroid hormones serve many functions in animals - including salt balance, metabolic function and sexual function Copyright © 1999 by Harcourt Brace & Company 41 Biochemistry 2/e - Garrett & Grisham Plant Sterols—Natural Cholesterol Fighters highly effective in blocking the absorption of cholesterol itself by intestinal cells Copyright © 1999 by Harcourt Brace & Company 42 Biochemistry 2/e - Garrett & Grisham 17β-Hydroxysteroid Dehydrogenase Deficiency the principal male sex steroid hormone Copyright © 1999 by Harcourt Brace & Company 43 Biochemistry 2/e - Garrett & Grisham Thank for watching Copyright © 1999 by Harcourt Brace & Company ... Biochemistry 2/e - Garrett & Grisham Classes of Lipids • • • • • • All biological lipids are amphipathic Fatty acids Triacylglycerols Glycerophospholipids Sphingolipids Waxes Isoprene-based lipids. .. characteristic lipid bilayers • types of phospholipids: phosphoglycerides and sphingomyelins Copyright © 1999 by Harcourt Brace & Company 14 Biochemistry 2/e - Garrett & Grisham 8.3 Glycerophospholipids... Copyright © 1999 by Harcourt Brace & Company 15 Biochemistry 2/e - Garrett & Grisham 8.3 Glycerophospholipids Glycerophospholipids are phospholipids but not necessarily vice versa • the prochirality