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Premium member Presentation Transcript CARBOHYDRATE METABOLISM: CARBOHYDRATE METABOLISM Kadek Rachmawati, M.Kes.,DrhCARBOHYDRATE DIGESTION: CARBOHYDRATE DIGESTION AMYLUM digestion by amylase enzymeDisaccharides digestion: Disaccharides digestionPowerPoint Presentation: Glucose is the most important carbohydrate Glucose is the major metabolic fuel of mammals, except ruminants Monosaccharide from diet : - Glucose - Fructose - Galactose Fructose and Galactose glucose at the liverGalactose Metabolism: Galactose MetabolismFructose Metabolism: Fructose MetabolismPowerPoint Presentation: Blood glucose carbohydrate metabolism exist are : 1. Glycolisis 2. Glycogenesis 3. HMP Shunt 4. Oxidation of Pyruvate 5. Kreb’s Cycle 6. Change to lipids Fasting blood glucose carbohydrate metabolism : 1. Glycogenolisis 2. GluconeogenesisGLYCOLISIS: GLYCOLISIS Glycolisis oxidation of glucose energy It can function either aerobically or anaerobically pyruvate lactate Occurs in the cytosol of all cell AEROBICALLY GLYCOLYSIS : Pyruvate Mitochondria oxidized to Asetil CoA Kreb’s Cycle CO2 + H2O + ATPGlycolisis : GlycolisisPowerPoint Presentation: Most of the reaction of glycolysis are reversible, except of three reaction : 1. Glucose Glucose-6-phosphate, catalyzed by Hexokinase / Glucokinase Hexokinase : - Inhibited allosterically by its product glucose-6-p - Has a high affinity for its substrate glucose - available at all cell, except liver and islet cellPowerPoint Presentation: Glucokinase : - available at liver and islet cell - in the liver to remove glucose from the blood after meal 2. Fructose-6-P Fructose-1,6-biP - catalyzed by Phosphofructokinase enzyme - Irreversible - Rate limiting enzyme in glycolysis 3. Phosphoenolpyruvate Enol Pyruvate - Catalyzed by Pyruvate kinase enzyme Oxidation of 1 mol glucose 8 mol ATP and 2 mol PyruvatePowerPoint Presentation: ANAEROBICALLY GLYCOLYSIS : - The reoxidation of NADH through the respiratory chain to oxygen is prevented - Pyruvate is reduced by the NADH to lactate, by Lactate dehidrogenase enzyme Lactate dehydrogenase Pyruvate + NADH + H + Lactate + NAD + - Oxidation 1 mol glucose via anaerobically glycolysis 2 mol ATPPowerPoint Presentation: ANAEROBICALLY GLYCOLYSIS : Respiratory chain is absence Reoxidation of NADH NAD + via Respiratory chain is inhibited Reoxidation of NADH via lactate formation allows glycolysis to proceed in the absence of oxygen by regenerating sufficient NAD +GLYCOLYSIS IN ERYTHROCYTE: GLYCOLYSIS IN ERYTHROCYTE Erythrocyte lack mitochondria respiratory chain and Kreb’s cycle are absence Always terminates in lactate In mammals the reaction catalyzed by phosphoglycerate kinase may be bypassed by a process that catalyzed Biphosphoglycerate muta- se Its does serve to provide 2,3-biphosphoglycerate bind to hemoglobin decreasing its affinity for oxygen oxygen readily available to tissuesGLYCOLYSIS IN ERYTHROCYTE: GLYCOLYSIS IN ERYTHROCYTEOXIDATION OF PYRUVATE: OXIDATION OF PYRUVATE Occur in mitochondria Oxidation of 1 mol Pyruvate 1 mol Asetyl-CoA + 3 mol ATP CH 3 COCOOH + HSCoA + NAD + CH 3 CO-SCoA + NADH (Pyruvate) (Asetyl-CoA) Catalyzed by Pyruvate dehydrogenase enzyme This enzyme need CoA as coenzyme In Thiamin deficiency, oxydation of pyruvate is impaired lactic and pyruvic acidOXIDATION OF PYRUVATE: OXIDATION OF PYRUVATEGLYCOGENESIS: GLYCOGENESIS Synthesis of Glycogen from glucose Occurs mainly in muscle and liver cell The reaction : Glucose Glucose-6-P Hexokinase / Glucokinase Glucose-6-P Glucose-1-P Phosphoglucomutase Glucose-1-P + UTP UDPG + Pyrophosphate UDPG PyrophosphorylaseGLYCOGENESIS: GLYCOGENESIS Glycogen synthase catalyzes the formation of α -1,4-glucosidic linkage in glycogen Branching enzyme catalyzes the formation of α -1,6-glucosidic linkage in glycogen Finally the branches grow by further additions of 1 → 4-gucosyl units and further branching (like tree!)SYNTHESIS OF GLYCOGEN: SYNTHESIS OF GLYCOGENSYNTHESIS OF GLYCOGEN : SYNTHESIS OF GLYCOGENGLYCOGENESIS AND GLYCOGENOLYSIS PATHWAY: GLYCOGENESIS AND GLYCOGENOLYSIS PATHWAYGlycogenesis Glycogenolysis: Glycogenesis GlycogenolysisGLYCOGENOLYSIS: GLYCOGENOLYSIS The breakdown of glycogen Glycogen phosphorilase catalyzes cleavage of the 1 →4 linkages of glycogen to yield glucose-1-phosphate α (1→4)→ α (1→4) glucan transferase transfer a trisaccharides unit from one branch to the other Debranching enzyme hydrolysis of the 1→6 linkages The combined action of these enzyme leads to the complete breakdown of glycogen.GLYCOGENOLYSIS: GLYCOGENOLYSIS Phosphoglucomutase Glucose-1-P Glucose-6-P Glucose-6-phosphatase Glucose-6-P Glucose Glucose-6-phosphatase enzyme a spesific enzyme in liver and kidney, but not in muscle Glycogenolysis in liver yielding glucose export to blood to increase the blood glu- cose concentration In muscle glucose-6-P glycolysisGLUCONEOGENESIS: GLUCONEOGENESIS Pathways that responsible for converting noncarbohydrate precursors to glucose or glycogen In mammals occurs in liver and kidney Major substrate : 1. Lactic acid from muscle, erythrocyte 2. Glycerol from TG hydrolysis 3.Glucogenic amino acid 4. Propionic acid in ruminantPowerPoint Presentation: Gluconeogenesis meets the needs of the body for glucose when carbohydrate is not available from the diet or from glycogenolysis A supply of glucose is necessary especially for nervous system and erythrocytes. The enzymes : 1. Pyruvate carboxylase 2. Phosphoenolpyruvate karboxikinase 3. Fructose 1,6-biphosphatase 4. Glucose-6-phosphataseGLUCONEOGENESIS: GLUCONEOGENESISGLUCONEOGENESIS FROM AMINO ACID: GLUCONEOGENESIS FROM AMINO ACIDGLUCONEOGENESIS FROM PROPIONIC ACID: GLUCONEOGENESIS FROM PROPIONIC ACIDCORY CYCLE: CORY CYCLEHMP SHUNT/HEXOSE MONO PHOSPHATE SHUNT = PENTOSE PHOSPHATE PATHWAY: HMP SHUNT/HEXOSE MONO PHOSPHATE SHUNT = PENTOSE PHOSPHATE PATHWAY An alternative route for the metabolism of glucose It does not generate ATP but has two major function : 1. The formation of NADPH synthesis of fatty acid and steroids 2. The synthesis of ribose nucleotide and nucleic acid formationHMP SHUNT: HMP SHUNT Active in : liver, adipose tissue, adrenal cortex, thyroid, erythrocytes, testis and lactating mammary gland Its activity is low in muscle In erythrocytes : HMP Shunt provides NADPH for the reduction of oxidized glutathione by glutathione reductase reduced glutathi- one removes H2O2 glutathione peroxidaseHMP SHUNT: HMP SHUNT Glutathione reductase G-S-S-G 2-G-SH (oxidized glutathione) (reduced glutathione) Glutathione peroxidase 2-G-SH + H2O2 G-S-S-G + 2H2O This reaction is important accumulation of H2O2 may decrease the life span of the erythrocyte damage to the membrane cell hemolysisHMP SHUNT: HMP SHUNTBLOOD GLUCOSE: BLOOD GLUCOSE Blood glucose is derived from the : 1. Diet the digestible dietary carbohy- drate yield glucose blood 2. Gluconeogenesis 3. Glycogenolysis in liver Insulin play a central role in regulating blood glucose blood glucose Glucagon blood glucose Growth hormone inhibit insulin activity Epinefrine stress blood glucoseGood luck!! Thank you: Good luck!! Thank you You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.