Carbohydrate metabolism

metabolism of carbohydrate

1. CARBOHYDRATE METABOLISM AND REGULATION OF BLOOD SUGAR DR CHIRAG M.A. Dept of ORAL & MAXILLOFACIAL SURGERY 1

2. CONTENTS INRODUCTION TRANSPORTATION GLYCOLYSIS GLUCONEOGENESIS GLYCOGENESIS GLYCOGENOLYSIS HMP SHUNT PATHWAY CONCLUSION 2

3. INTRODUCTION IN PLANTS - CARBONDIOXIDE + WATER GLUCOSE (STORED AS STARCH OR CONVERTED TO CELLULOSE) IN ANIMALS - FAT + PROTEIN – CONVERTED TO CARBOHYDRATE 3

4. CLASSIFICATION OF CARBOHYDRATE Monosaccharides ERYTHROSE, RIBOSE, GLUCOSE Disaccharides SUCROSE, LACTOSE Oligosaccharides MALTOTRIOSE Polysaccharides STARCH,CELLULOSE 4

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6. TRANSPORTATION 6

7. GLYCOLYSIS EMBDEN MEYERHOF PATHWAY ALL CELLS OF BODY ONLY SOURCE OF ENERGY FOR ERYTHROCYTE SEVERAL STEPS ENERGY PRODUCED IS DIFFERRENT FOR AEROBIC AND ANEROBIC CONDITION 7

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10. REGULATION OF GLYCOLYSIS REGULATED BY THREE ENZYMES, REACTION 1 HEXOKINASE - INHIBITED BY HIGH LEVELS OF GLUCOSE-6-PHOSPHATE, WHICH PREVENTS THE PHOSPHORYLATION OF GLUCOSE. REACTION 3 PHOSPHOFRUCTOKINASE - INHIBITED BY HIGH LEVELS OF ATP AND ACTIVATED BY HIGH LEVELS OF ADP AND AMP. REACTION 10 PYRUVATE KINASE - INHIBITED BY HIGH LEVELS OF ATP OR ACETYL COA. 10

11. PATHWAYS FOR PYRUVATE AEROBIC CONDITION THREE-CARBON PYRUVATE IS DECARBOXYLATED. TWO-CARBON ACETYL CoA AND CO 2 ARE PRODUCED. O O PYRUVATE || || DEHYDROGENASE CH 3 — C — C — O - + HS — CoA + NAD + PYRUVATE O || CH 3 — C —S— CoA + CO 2 + NADH ACETYL CoA 11

12. UNDER ANAEROBIC CONDITIONS PYRUVATE IS REDUCED TO LACTATE. NADH OXIDIZES TO NAD + ALLOWING GLYCOLYSIS TO CONTINUE. O O LACTATE || || DEHYDROGENASE CH 3 — C — C — O - + NADH + H + PYRUVATE OH O | || CH 3 — CH — C — O - + NAD + LACTATE 12

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14. GLUCONEOGENESIS GLUCOSE SYNTHESIS 14

15. GLUCONEOGENESIS SITE – MAINLY LIVER BUT ALSO RENAL CORTEX PARTLY MITOCHONDRIAL PARTLY CYTOPLASMIC GLUCOSE SYNTHESIZED FROM NONCARBOHYDRATES LACTATE, SOME AMINO ACIDS, AND GLYCEROL AFTER THEY ARE CONVERTED TO PYRUVATE OR OTHER INTERMEDIATES SEVEN REACTIONS ARE THE REVERSE OF GLYCOLYSIS AND USE THE SAME ENZYMES THREE REACTIONS ARE NOT REVERSIBLE. REACTION 1 HEXOKINASE REACTION 3 PHOSPHOFRUCTOKINASE REACTION 10 PYRUVATE KINASE 15

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18. CORI CYCLE/ LACTIC ACID CYCLE IS THE FLOW OF LACTATE AND GLUCOSE BETWEEN THE MUSCLES AND THE LIVER. OCCURS WHEN ANAEROBIC CONDITIONS OCCUR IN ACTIVE MUSCLE AND GLYCOLYSIS PRODUCES LACTATE. OPERATES WHEN LACTATE MOVES THROUGH THE BLOOD STREAM TO THE LIVER, WHERE IT IS OXIDIZED BACK TO PYRUVATE. CONVERTS PYRUVATE TO GLUCOSE, WHICH IS CARRIED BACK TO THE MUSCLES. 18

19. GLYCOGEN METABOLISM 19

20. GLYCOGENESIS STORES GLUCOSE BY CONVERTING GLUCOSE TO GLYCOGEN. STORED IN LIVER AND MUSCLES USED DURING STARVATION DOES NOT OPERATE WHEN ENERGY STORES (GLYCOGEN) ARE FULL, WHICH MEANS THAT ADDITIONAL GLUCOSE IS CONVERTED TO BODY FAT. FATTY ACID OXIDATION FOR ENERGY AFTER 18 HRS OF STARVATION MUSCLE GLYCOGEN IS RESERVE FOR MUSCLE CONTRACTION 20

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22. GLUCOSE-6-PHOSPHATE IS CONVERTED TO GLUCOSE-1-PHOSPHATE 22

23. UTP ACTIVATES GLUCOSE-1-PHOSPHATE TO FORM UDP-GLUCOSE AND PYROPHOSPHATE (PP I ). 23

24. THE GLUCOSE IN UDP-GLUCOSE ADDS TO GLYCOGEN. UDP-GLUCOSE + GLYCOGEN GLYCOGEN -GLUCOSE + UDP THE UDP REACTS WITH ATP TO REGENERATE UTP. UDP + ATP UTP + ADP PRIMER MOLECULE – GLYCOGENIN ENZYME - GLYCOGEN SYNTHASE 24

25. GLYCOGENOLYSIS GLYCOGEN IS BROKEN DOWN TO GLUCOSE. GLUCOSE MOLECULES ARE REMOVED ONE BY ONE FROM THE END OF THE GLYCOGEN CHAIN TO YIELD GLUCOSE-1-PHOSPHATE. 25

26. GLYCOGENOLYSIS IS ACTIVATED BY GLUCAGON (LOW BLOOD GLUCOSE). BONDS GLUCOSE TO PHOSPHATE TO FORM GLUCOSE-1-PHOSPHATE. GLYCOGEN-GLUCOSE + P I GLYCOGEN + GLUCOSE-1-PHOSPHATE 26

27. THE GLUCOSE-1-PHOSPHATE ISOMERIZES TO GLUCOSE-6-PHOSPHATE, WHICH ENTERS GLYCOLYSIS FOR ENERGY PRODUCTION. 27

28. HMP SHUNT PATHWAY 10% GLUCOSE/DAY IN THIS PATHWAY HEXOSE MONO PHOSPHATE PATHWAY PENTOSE PHOSPHATE PATHWAY (PPP) DICKENS HORECKER PATHWAY GENERATION OF REDUCED NADPH AND PENTOSE PHOSPHATE FOR NUCLEOTIDE SYNTHESIS TWO PHASES - OXIDATIVE - NON OXIDATIVE 28

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30. SIGNIFICANCE OF HMP SHUNT FOR LIPID SYNTHESIS FOR STEROID SYNTHESIS FOR RIBOSE SYNTHESIS (REQ FOR NUCLEOTIDE) FREE RADICAL SCAVENGING DETOXIFICATION OF DRUGS ERYTHROCYTE MEMBRANE INTEGRITY PRESERVING TRANSPARENCY OF LENS OF EYE (NADPH IS REQ.) 30

31. CARBOHYDRATES IN DENTAL CARIES • FERMENTABLE CARBOHYDRATES CAUSES LOSS OF CARIES RESISTANCE. • CARIES PROCESS IS AN INTERPLAY BETWEEN ORAL BACTERIA, LOCAL CARBOHYDRATES & TOOTH SURFACE BACTERIA + SUGARS+ TEETH ORGANIC ACIDS 31 CARIES

32. ROLE OF CARBOHYDRATES IN PERIODONTAL DISEASE ABNORMAL GLUCOSE METABOLISM DIABETES MELLITUS PERIODONTAL DISEASE EXCESSIVE CARBOHYDRATE INTAKE OBESITY PERIODONTAL DISEASE 32

33. CONCLUSION • CARBOHYDRATE ARE THE MEASURE SOURCE OF ENERGY FOR THE LIVING CELLS. GLUCOSE IS THE CENTRAL MOLECULE IN CARBOHYDRATE METABOLISM, ACTIVELY PARTICIPATING IN A NUMBER OF METABOLIC PATHWAY. • ONE COMPONENT OF ETIOLOGY OF DENTAL CARIES IS CARBOHYDRATE WHICH ACT AS SUBSTRATE FOR BACTERIA. EVERY EFFORT SHOULD BE MADE TO REDUCE SUGAR INTAKE FOR HEALTHY TOOTH. 33

34. 34 THANK YOU