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Metabolism of saccharides

Metabolism of saccharides. Vladimíra Kvasnicová. Glucose enter the cells by. free diffusion facilitated diffusion active transport secondary active transport. Glucose enter the cells by. free diffusion facilitated diffusion active transport secondary active transport.

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Metabolism of saccharides

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  1. Metabolism of saccharides Vladimíra Kvasnicová

  2. Glucose enter the cells by • free diffusion • facilitated diffusion • active transport • secondary active transport

  3. Glucose enter the cells by • free diffusion • facilitated diffusion • active transport • secondary active transport

  4. Insulin-dependent transport of glc into the cell is found in the • liver • erytrocyte • adipose tissue • muscle

  5. Insulin-dependent transport of glc into the cell is found in the • liver • erytrocyte • adipose tissue • muscle

  6. Glucose transport into cells: facilitated diffusion(protein transporter GLUT – various types) ERYTROCYTES NERVOUS TISSUE - insulin-independent transport The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  7. HEPATOCYTES - insulin-independent transport The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  8. FATTY TISSUE MUSCLES - insulin-DEPENDENT transport insulin increases number of glc transporters The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  9. The figure was accepted from Trends in Biochemical Sciences, reference edition, volume 6, str. 209.Elsevier/North-Holland Biomedical Press, 1981.

  10. Secondary-active transport of GLC: symport with Na+ - small intestine, kidneys The figure was accepted fromDevlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley‑Liss, Inc., New York, 1997. ISBN 0‑471‑15451‑2

  11. Glucose from a diet can be used • as an energy source for cells • for glycogen synthesis • for formation of fat (= energy store) • as a main substrate for production of NADPH

  12. Glucose from a diet can be used • as an energy source for cells • for glycogen synthesis • for formation of fat (= energy store) • as a main substrate for production of NADPH

  13. Glc-6-P !!! + NADPH = hepatocyte The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  14. The figure was accepted fromDevlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley‑Liss, Inc., New York, 1997. ISBN 0‑471‑15451‑2

  15. 1st phase 2nd phase 3rd phase

  16. The enzymes you must know The figure is found athttp://web.indstate.edu/thcme/mwking/glycolysis.html (Jan 2007)

  17. The figure is found athttp://web.indstate.edu/thcme/mwking/glycolysis.html (Jan 2007)

  18. The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  19. Products of aerobic glycolysis 2 Products of anaerobic glycolysis NADHwas consumed in conversion of pyruvate to lactate 2 The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  20. Glycolysis(= oxidative cleavage of glucose) • is located in a mitochondrion • can proceed under anaerobic conditions as well • produces 2 moles of pyruvate / 1 mole of Glc • generates 2 moles of ATP as a net energy acquisition

  21. Glycolysis(= oxidative cleavage of glucose) • is located in a mitochondrion • can proceed under anaerobic conditions as well • produces 2 moles of pyruvate / 1 mole of Glc • generates 2 moles of ATP as a net energy acquisition

  22. Enzyme hexokinase • catalyzes esterification of glucose • has higher affinity to glucose than glucokinase • phosphorylates fructose as well • is found in a cytoplasm of many cells

  23. Enzyme hexokinase • catalyzes esterification of glucose • has higher affinity to glucose than glucokinase • phosphorylates fructose as well • is found in a cytoplasm of many cells

  24. IRREVERSIBLE REACTION The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  25. The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  26. Enzyme 6-phosphofructokinase-1 (PFK-1) • is a main regulatory enzyme of glycolysis • converts fructose-1,6-bisphosphate to fructose-6-phosphate • is activated by citrate and  ATP/ADP • is regulated by insulin

  27. Enzyme 6-phosphofructokinase-1 (PFK-1) • is a main regulatory enzyme of glycolysis • converts fructose-1,6-bisphosphate to fructose-6-phosphate • is activated by citrate and  ATP/ADP • is regulated by insulin

  28. IRREVERSIBLE REACTION The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  29. NADH+H+ forming in glycolysis • is a coenzyme of oxidoreductases • can be reoxidized back to NAD+ in a conversion of pyruvate to lactate • can be used in a reduction of malate to oxaloacetate • is a source of reducing equivalents enteringa respiratory chain, but only under aerobic conditions

  30. NADH+H+ forming in glycolysis • is a coenzyme of oxidoreductases • can be reoxidized back to NAD+ in a conversion of pyruvate to lactate • can be used in a reduction of malate to oxaloacetate • is a source of reducing equivalents enteringa respiratory chain, but only under aerobic conditions

  31. Products of aerobic glycolysis 2 Products of anaerobic glycolysis NADHwas consumed in conversion of pyruvate to lactate 2 The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  32. The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  33. The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  34. Transport of reducing equivalents to mitochondria The figure was accepted fromDevlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley‑Liss, Inc., New York, 1997. ISBN 0‑471‑15451‑2 MALATE-ASPARTATE SHUTTLE

  35. GLYCEROL PHOSPHATE SHUTTLE The figure was accepted fromDevlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley‑Liss, Inc., New York, 1997. ISBN 0‑471‑15451‑2

  36. 2,3-bisphosphoglycerate (2,3-BPG) • belongs among energy rich compounds • is formed from glyceraldehyde-3-phosphate by phosphorylation using inorganic phosphate • can be transformed to 3-phosphoglycerate, ATP is simultaneously formed from ADP • is formed only in the liver as a shunt of glycolysis

  37. 2,3-bisphosphoglycerate (2,3-BPG) • belongs among energy rich compounds • is formed from glyceraldehyde-3-phosphate by phosphorylation using inorganic phosphate • can be transformed to 3-phosphoglycerate, ATP is simultaneously formed from ADP • is formed only in the liver as a shunt of glycolysis

  38. 2,3-BPG shunt IN ERYTROCYTES: 2,3-BPG  affinity of Hb to O2 The figure was accepted fromDevlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley‑Liss, Inc., New York, 1997. ISBN 0‑471‑15451‑2

  39. ATP is formed in the reactions of glycolysis • phosphoenolpyruvate (PEPA) → pyruvate • glucose → glucose-6-phosphate • fructose-1,6-bisphosphate→ fructose-6-phosphate • glyceraldehyde-3-phosphate→ 1,3-bisphosphoglycerate

  40. ATP is formed in the reactions of glycolysis • phosphoenolpyruvate (PEPA) → pyruvate • glucose → glucose-6-phosphate • fructose-1,6-bisphosphate→ fructose-6-phosphate • glyceraldehyde-3-phosphate→ 1,3-bisphosphoglycerate

  41. IRREVERSIBLE REACTION = substrate level phosphorylation (ATP formation using energy released from cleavage of an energy rich compound = macroergic compound) The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  42. Pi + = substrate level phosphorylation The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  43. Pyruvate can be transformed by • carboxylation to acetyl-CoA • reduction to lactate • oxidative decarboxylation to oxaloacetate • transamination to aspatate

  44. Pyruvate can be transformed by • carboxylation to acetyl-CoA • reduction to lactate • oxidative decarboxylation to oxaloacetate • transamination to aspatate

  45. = transamination = reduction = carboxylation = oxidative decarboxylation The figure is found athttp://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)

  46. Choose correct statements about regulation of glycolysis • it is activated by insulin • it is activated by glucagon • regulatory enzymes of glycolysis are kinases •  pH inhibits glycolysis

  47. Choose correct statements about regulation of glycolysis • it is activated by insulin • it is activated by glucagon • regulatory enzymes of glycolysis are kinases •  pH inhibits glycolysis

  48. Regulation of glycolysis

  49. Gluconeogenesis proceeds as a „reversed glycolysis“ with exception of3 reactions ! The figure was found at http://www.biochem.arizona.edu/classes/bioc462/462b/graphics/GlycolysisGNGLehn4Fig14-16.jpg (Dec 2007)

  50. glucose entering glycolysis pyruvateentering gluconeogenesis The figure has been adopted from J.Koolman, K.H.Röhm / Color Atlas of Biochemistry, 2nd edition, Thieme 2005

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