BMS100 Carbohydrates Post-learning Material PDF

Carbohydrates Carbohydrate Post-learning Material Dr. I. Fraser BMS100 Important Monosaccharides Objectives Recognize the structures of glucose, fructose, galactose Discuss their functions/uses Identify structural features of monosaccharides Glucose D-isomer is aka dextrose Most important carbohydra...

Carbohydrates Carbohydrate Post-learning Material Dr. I. Fraser BMS100 Important Monosaccharides Objectives Recognize the structures of glucose, fructose, galactose Discuss their functions/uses Identify structural features of monosaccharides Glucose D-isomer is aka dextrose Most important carbohydrate in biology: primary fuel for living cells Broken down for energy via what metabolic pathway? RBC’s rely on this for energy, as they do not have mitochondria Review: what energy producing pathways require the mitochondria? Stored as starch in plants and glycogen in animals Component of various disaccharides: lactose à maltose à sucrose à glucose and galactose glucose and glucose glucose and fructose Fructose Levulose Fruit Sugar HO C H2 6 O 5 D-isomer is aka levulose A ketohexose isomer of glucose Found in honey & fruits H HO OH H 3 H H 1 4 sweetest naturally occurring sugar, estimated to be twice as sweet as sucrose. HO C Fructose is produced from digestion of sucrose (glucose + fructose) H 2 H OH O H2 H HO O HO CH2OH H Sucrose (glucose a1- b2 fructose) Galactose An epimer of glucose (review: what does epimer mean?) Often attached to lipids to make glycolipids, or to proteins to make proteoglycans and glycoproteins Remember, oligosaccharides are often O- linked to proteins via N-acetyl-galactosamine Component of lactose Found in dairy products as part of lactose Structural Features of Monosaccharides Questions: - How can you distinguish the “gluco”s from the “galacto”? - Why are all of these designated “D” and “beta” sugars? - Why do they all have an “amine” suffix? NH2 Beta-D-glucosamine Beta-D-galactosamine - Why is “N-acetyl” a prefix in the bottom picture? N-acetyl-beta-D-glucosamine Disaccharides Objectives List the monosaccharide components of maltose, lactose and sucrose Recognize their structures Discuss their functions/uses Describe what is happening in someone who is lactose intolerant Given a diagram, be able to provide structural names for disaccharides and name their links Determine whether a disaccharide is a reducing sugar Lactose HO C H2 HO C H2 6 6 5 HO H O 5 1 4 H OH 3 H H O H OH H 3 2 H OH 4 H H 3 H H OH O 5 H 2 OH H O H 4 H OH Its full name is β-Dgalactopyranosyl-(1® 4)-?-D-glucopyranose O OH 1 OH 3 H It is composed of galactose & glucose in a β(1®4) linkage 2 6 1 OH H HO C H2 6 HO H O 1 4 HO C H2 5 Lactose is a milk sugar H 2 OH H Question: ? = α in which diagram (top or bottom); and ? = β in which diagram? Lactose Intolerance Mechanism A deficiency of the lactase enzyme in the small intestine means that lactose is not broken down into its monosaccharides (review: which ones?) Remember, during digestion, only small molecules (ie monosaccharides, not disaccharides) can be absorbed The undigested lactose therefore reaches the large intestine, where it is metabolized by bacteria The metabolic products can lead to the gas and bloating associated with lactose intolerance Maltose Maltose is a malt sugar HO C H2 HO C H2 6 6 5 H H O 5 1 4 HO OH H 3 H H H O OH H 4 H OH HO 3 H OH It is a cleavage product of starch (e.g., amylose) that does not appear to exist freely in nature 2 OH Question 1: Name the glycosidic link HO C H2 6 O 5 H 1 OH H 3 2 6 H H 1 4 HO C H2 5 H O H 2 OH H O 4 H O OH 1 OH 3 H H 2 OH H Question 2: Maltose undergoes mutarotation in solution to create an equilibrium mixture of alpha and beta maltoses – which diagram is which? Isomaltose HO C H2 6 O 5 Isomaltose is an isomer of maltose FYI: Formed by treating high maltose corn syrup with the enzyme transglycosidase The structural difference between maltose and isomaltose is its glycosidic link Name the link for isomaltose H 4 HO H H 1 OH H 3 H 2 OH O H CH 6 5 H 4 HO H O H 1 OH 3 H H 2 OH OH Sucrose HOCH2 6 O 5 H H H 1 4 HO OH H 3 2 H OH O HOCH2 H H HO O HO CH2OH Sucrose is a common table sugar It has a glycosidic bond linking the anomeric carbons of both glucose & fructose, so both need to be taken into account when naming the glycosidic link: Sucrose has an α,β(1®2) glycosidic linkage. The full name of sucrose is α-Dglucopyranosyl-(1®2)-β-Dfructofuranose - Why “furanose”? H Sucrose (glucose a1- b2 fructose) Questions Are maltose, lactose, sucrose reducing sugars? Why or why not? Homopolysaccharides Objectives Identify the reducing and non-reducing ends of homopolysaccharides, and outline the significance of the non-reducing ends Name the straight chain and branch point links of homopolysaccharides Describe the structure and function of cellulose Amylose Review the reducing and non-reducing ends on the next two slides Amylose C1 carbon has nothing attached to the OH = reducing end Amylose Reducing End HO C H2 HO C H2 6 6 5 H 1 O 4 H O 5 H 1 OH 3 H H 2 OH H O 4 H O H 1 OH 3 H H 2 OH OH Amylose C1 carbon is linked to the next monosaccharide = non reducing end Amylose Noneducing End HO C H2 HO C H2 6 6 5 H 4 HO H O 5 H 1 OH 3 H H OH 2 H O 4 H O H 1 OH 3 H H 2 OH O 4 Amylopectin Review the branching structure of amylopectin on the next slide Amylopectin Amylopectin Branch points – create more nonreducing ends Amylopectin Branch point links Identify and name the branch point link on the next slide Amylopectin HO C H2 6 O 5 H 1 O 4 H 1 OH H 3 2 H OH 1 O 4 H O 5 H H H 1 OH O 4 H H 6 2 OH O 5 OH H H 2 OH H H 1 3 3 HO C H2 6 6 H O HCH HO C H2 5 H O 4 H O H 1 OH 3 H H 2 OH O 4 Amylopectin Straight chain links On the next two slides: Identify which slide highlights the reducing end(s), and which highlights the non-reducing end(s) Name the straight chain links Amylopectin HO C H2 HO C H2 6 6 5 H 4 HO H O 5 1 OH 3 H H 2 OH H H O 4 H O H 1 OH 3 H H 2 OH O 4 Amylopectin HO C H2 HO C H2 6 6 5 H 1 O 4 H O 5 1 OH 3 H H 2 OH H H O 4 H O H 1 OH 3 H H 2 OH OH Homopolysaccharides Structural Homopolysaccharides cellulose D-glucose in beta (1,4) links CH2OH H O H OH H OH H 1 O H H OH 6CH OH 2 5 O H 4 OH 3 H H 1 2 OH O O H OH CH2OH CH2OH CH2OH H Note: beta links! H H O O H OH H OH cellulose O H O H OH H OH OH H H H H H H H OH Homopolysaccharides Cellulose function Provides structure to plant cell walls What do animals do with it? Cows and termites can digest it FYI: Via gut microbes in cows and cellulase enzyme in termites Humans cannot digest Physiologically: used for dietary fiber Other applications: wood, paper, fabric Cellulose Review the reducing and non-reducing ends on the next two slides Homopolysaccharides: Cellulose HO C H2 HO C H2 6 6 5 H 4 HO H O 5 1 OH 3 H H 2 OH H O H 4 H O 1 OH 3 H Nonreducing end H 2 OH O 4 Homopolysaccharides: Cellulose HO C H2 HO C H2 6 6 5 H O H O 5 1 4 OH 3 H H O H 4 H 2 OH Reducing end H O H 1 OH 3 H H 2 OH OH Heteropolysaccharides Review: what is the difference between the homopolysaccharides you just saw and the heteropolysaccharides that you will review next? To answer, fill in the blanks: Homopolysaccharides are made up of _(one word)_____ type of monosaccharide, where as heteropolysaccharides are made up of _(a few words)_ type of monosaccharide Heteropolysaccharides Objectives Name the 3 common monosaccharides found in GAGs Identify common monosaccharide derivatives in GAGs (ex amino sugars, acid sugars, etc) Describe mucopolysaccharidoses Heteropolysaccharides There are 3 common monosaccharides found in GAGs, which are often modified Previously mentioned: Glucose (as glucuronic acid or glucosamine) and galactose (often as galactosamine) Also: idose (as iduronic acid, which is oxidized idose) CH2OH H OH OH H Idose Iduronic acid Heteropolysaccharides The following slides include pictures of the various disaccharides that make GAGs. Identify the following features: Any glucose and galactose Amino groups Acid groups Acetyl groups Sulfates Note: you do NOT need to memorize the disaccharide components of the various GAGs. GAG Structures H2 COSO3 HO C H2 6 6 5 HO H O 1 4 H 5 O 3 H H 2 OH H O H 4 H O O 1 OH 3 H Keratan sulfate H H 2 HNCCH3 O n GAG Structures H2 COH H 5 H COO 6 O SO3 5 H O 6 1 4 O OH 3 H H H OH O 1 4 O H O 3 2 O H Dermatan sulfate H H 2 HNCCH3 O n GAG Structures H2COSO3 COO 6 6 5 H O H 1 4 O H O OH 3 H H H 5 H OH O 1 4 O H O 3 2 O H H H 2 HNCCH3 O Chondroitin 6-sulfate n GAG Structures H2 COH COO 6 5 H 6 O H H 1 4 O 5 OH 3 H H 2 OH H O H O O 1 4 O H O 3 H Hyaluronic Acid H H 2 HNCCH3 O n Mucopolysaccharidosis Pathology associated with proteoglycans = mucopolysaccharidosis Excess accumulation of proteoglycans due to missing or defective lysosomal enzymes Example to know: Hurlers syndrome Autosomal recessive Deficient enzyme = L-iduronidase Can’t remove iduronic acid when degrading proteoglycans, so get accumulation of dermatan sulfate and heparin Symptoms include: mental retardation, skeletal deformities Treatment options: gene therapy, bone marrow transplant Optional Resources If you would like an more in-depth explanation of some of the carbohydrates material, you can use the links to the videos on the next slides Note that these videos may include extra details for the purposes of providing a detailed explanation. In terms of assessment, only the level of detail presented on the slides that were covered in the pre/post learning and in class will be tested. Aldoses, Ketoses, Fischer Projections and Epimers https://www.youtube.com/watch?v=ECKrQu0Y2PI Cyclic form of carbohydrates https://www.youtube.com/watch?v=H7z1vNc1jos &t=216s Disaccharides (Maltose, Lactose and Sucrose) https://www.youtube.com/watch?v=Kj15mH5zB6Y &t=38s Polysaccharides (Glycogen, Starch and Cellulose) https://www.youtube.com/watch?v=e0ijBDroE48& t=367s