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Presentation on theme: "Glyconeogenesis."— Presentation transcript:

1 Glyconeogenesis

2 Origin of blood glucose
Food Glycogen (liver) Gluconeogenesis (liver) Blood sugar

3 Decrease of blood sugar
Disfunction of brain Confusion à coma In the absence of alternative substrate - serious consequences (ketonbodies) .à diabetes, overdose of insulin Cramps Sympathetic exitement hyperventillation, cold sweat

4 Synthesis of glucose – non carbohydrate precursors
Gluconeogenesis Synthesis of glucose – non carbohydrate precursors Daily utilisation of glucose: 160 g/day Glucose - Brain : 120 g/day In humours 20 g In glycogen 190 g Reserves for 24 hours in fasting

5 Gluconeogenesis Gluconeogenesis > fasting for 24 hours
Intensive excercise Source: Lactic acid aminoacids Glycerol Organ: Liver Kidney (1/10) Some in brain, in heartmuscle in striated muscle

6 DG of glycolysis (glucose à pyruvate) – 20 kcal/mole
Glyconeogenesis DG of glycolysis (glucose à pyruvate) – 20 kcal/mole Decrease in free energy in three stages 3 different „ways”

7 Irreversible steps In glycolysis In glyconeogenesis


9 Irreversible steps of glycolysis
hexokinase 1. Glucose + ATP à glucose-6-P + ADP phosphofructokinase 2. Fruktose-6-P + ATP à fructose-1,6-diP + ADP Piruvate kinase 3. PEP + ADP à pyruvate + ATP

10 Pyruvate à oxalacetate à phosphoenolpyruvate
Pyruvate-carboxylase Pyruvate + CO2 + ATP + H2O à oxaloacetate + ADP + Pi + 2H+ Phosphoenolpyruvate carboxykinase TP oxaloacetate + GTP ó PEP + GDP + CO2



13 Pyruvate carboxylase Intramitochondrial Prosthetic group: biotin

14 Signal – for more oxaloacetate
Allosteric activator: Acethyl~CoA Anaplerotic reaction Signal – for more oxaloacetate


16 Oxalacetate Gluconeogenesis Citric acid cycle Low amount of ATP
High amount of ATP Gluconeogenesis Citric acid cycle

17 Irreversible steps of glyconeogenesis
Fructose-1,6-diP 2. fructose-1,6-diP + H2O à fructose-6-P +Pi Glucose-6-phosphatase 3. glucose-6-P + H2O à glucose +Pi Absence in brain and muscle

18 Plasmamembrane of hepatocytes
Glucose-6-P GluT7 Glucse-6-phosphatase Glucose Pi ER-lumen GluT7 Cytosol GluT2 Plasmamembrane of hepatocytes Bloodplasma

19 The gluconeogenesis is „expensive”
2 pyruvate + 4 ATP + 2 GTP + 2 NADH + 4 H2O àà à à Glucose + 4 ADP + 2 GDP + 2 NAD+ + 2 H+ Irreversible Glycolysis Glucose + 2 ADP + 2 Pi + 2 NAD+ à à à à 2 pyruvate+ 2 ATP + 2 NADH + 2H++ 2 H2O

20 Citoplazmatikus PEP karboxikináz
NADH + H+ Citoplazmatikus PEP karboxikináz PEP NAD+ Oxálacetát Malát CO2 Malát PEP NAD+ Mitokonriális PEP karboxikináz CO2 NADH + H+ Oxálacetát Oxálacetát Piruvát karboxiláz CO2 CO2 Piruvát Piruvát Mitokondrium Piruvát Citoszól Piruvát NADH + H+ NAD+ Laktát



23 Glucoplastic aminoacids
Pyruvate Alanine Cystein Glycine Serine Triptophane .a-ketoglutarate Arginine Glutamate Glutamine Hisztidine Proline Succinyl-CoA Isoleucine Metionine Treonine Valine Fumarate Fenilalanin Tirozin Oxalacetate Aspartate Asparagine

24 Blood Blood Glucose Work (2) ADP + (2) Pi Glycolysis (2) ATP Lactate
(2) H+ Blood

25 Cori cycle Prevents lactic acidosis follow the glycolysis Liver
Musle, red blood cells Glucose Glucose pyruvate Lactic acid Lactic acid Prevents lactic acidosis follow the glycolysis

26 Alanin cyclus Transport of aminoacids in nontoxic form Liver Muscle
urea Glucose Glucose Amino acid NH2 NH3 Piruvate Glutamate glutamate Piruvate Alanin a-ketoglutarate a-ketoglutarate Alanin Transport of aminoacids in nontoxic form


28 Glucose tolerance test

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