Introduction to Carbohydrates PDF

NFNF1613 BASIC CONCEPT OF CELL FUNCTION Dr. Mohd Kaisan Mahadi Fakulti Farmasi, UKM [email protected] Lecture objectives: Define carbohydrates nomenclature Understand the groups of saccharides in chemical and descriptive terms. Understand differ...

NFNF1613 BASIC CONCEPT OF CELL FUNCTION Dr. Mohd Kaisan Mahadi Fakulti Farmasi, UKM [email protected] Lecture objectives: Define carbohydrates nomenclature Understand the groups of saccharides in chemical and descriptive terms. Understand different classes of carbohydrates. Know the glycosidic bonds. Understand the general role of carbohydrates. Basic Concept of Carbohydrates Sources of carbohydrate http://dailybrainstorms.com/wp-content/uploads/2015/06/Daily_brain_storms_Carbohydrates_.png https://foxvalleyfitness.files.wordpress.com/2015/02/good-carbs-vs-bad-carbs.jpg Definition The Molecule Very structurally diversed Basic building block : MONOSACCHARIDES Linked monosaccharides à OLIGOSACCHARIDES àPOLYSACCHARIDES http://chemistry2.csudh.edu/rpendarvis/1feb23.gif Monosaccharides (MS) Simplest form of carbohydrates Consist of: 1. 3 to 9 Carbon atoms 2. Aldehyde or Ketone group 3. Hydroxyl groups (multiple) http://archive.cnx.org/resources/... Carbohydrates nomenclature Based on the no of carbon chain. Functional group (aldehyde/ketone) Stereochemistry Glucose C6H12O6 Important metabolite in human Major free MS present in blood circulation Substrate for energy metabolism in cells Naming monosaccharides 3C à triose, 4C à tetrose, 5C à pentose… 6C à ?? , 7C à ??, 8C à ?? Aldohexose? Ketohexose? C-1 aldehyde in the open-chain form of glucose reacts with the C-5 hydroxyl group to form an intramolecular hemiacetal C-2 keto group in the open-chain form of a ketohexose, such as fructose, can form an intramolecular hemiketal by reacting with either the C-6 hydroxyl group to form a six- membered cyclic hemiketal or the C-5 hydroxyl group to form a five-membered cyclic hemiketal Alpha and Beta Glucose What can you tell about this? Oligosaccharides Linkage of 2 or more monosaccharides, via glycosidic bonds O-glycosidic bonds form between carbon atoms of adjacent MS via reactions of hydroxyl groups Multiple OH groups à various glycosidic linkages à various structures/types carbohydrates http://www.chem.latech.edu/~upali/chem102/image7EJ.JPG Disaccharides Common/abundant forms of disaccharides: Sucrose Lactose Maltose Dietary components Sucrose Common form/source: Sugar from cane or beet sucrase https://explorebiochemistryworld.files.wordpress.com/2013/02/glucose-fructose-sucrose.gif Lactose Common form/source: milk http://www.chem.latech.edu/~upali/chem102/imageHTM.JPG Human http://interactive-biology.com/wp-content/uploads/2012/08/Lactase-hydrolysis1-1024x232.png Bacteria http://www.web-books.com/MoBio/Free/images/Ch4H1.gif Maltose X + X à Maltose Maltose à X + X Y Glycosidases The family of enzyme that hydrolyzes glycosidic bonds Break down oligosaccharides à monosaccharides Examples: ?? Polysaccharides Large, complex oligosaccharides https://biochemistry3rst.files.wordpress.com/2014/02/fig-1-mcabe.jpg http://cnx.org/resources/ff24547bd43194a91783d82f3b805b5c/219_Three_Important_Polysaccharides-01.jpg Glycogen Homopolymers Storage form of glucose http://img.tfd.com/ggse/0b/gsed_0001_0006_0_img1079.png Produced via glycogenesis Break down to glucose via glycogenolysis http://www.scientificpsychic.com/fitness/glycogen.gif Starch Glucose storage form in plants Unbranched form: Amylose Branched form: Amylopectin Hydrolysed to glucose by α-amylase Cellulose Roles of carbohydrates 1. Energy stores, “fuels” and metabolic intermediates 2. Composition of RNA and DNA structure (example: ??) 3. Main constituent of plant cell walls (example: ??) 4. Involved in cellular processes and signaling as carb molecules linked to proteins and lipids  Glycoproteins/glycolipids Carbohydrate attached to proteins/lipids Glycosylation process Potential glycosation sites of proteins: N-linkage à Nitrogen atom of Asparagine residue of a protein O-linkage à Oxygen atom of Serine or Threonine residue of a protein May be important for a particular protein function eg. secretion, receptor signaling  https://animalcellbiology.files.wordpress.com/201 1/08/membrane-lipids-and-proteins.gif?w=460 https://www.researchgate.net/profile/Niraj_Kumar13/publication/51897355/figure/fig7/AS:302444325163008@1449119754013/Fig-7-The-structure-and-glycosylation-sites-of-EpoFc-Two-Erythropoietin-peptides-are.pn Summary References Berg, J.M., Tymoczko, J.L. & Stryer, L. 2010. Biochemistry. New York : W.H. Freeman & Co Ltd.