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1) Gluconeogenesis is the production of glucose from non-carbohydrate sources like lactate, glycerol, and amino acids. 2) It mainly occurs in the cytosol of cells and produces about 1 kg of glucose per day, which is essential for brain function and muscle energy needs. 3) Key reactions in gluconeogenesis involve converting pyruvate to phosphoenolpyruvate and fructose-1,6-bisphosphate to fructose-6-phosphate through various enzymes and cofactors. This allows precursors to re-enter glycolysis and ultimately form new glucose.

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Amoud medical school GLUCONEOGENESIS Dr. Mukhtar Jama Nour , MBBS, MD
INTRODUCTION The production of glucose from non carbohydrate compounds is known as gluconeogenesis. Lactate, pyruvate, glucogenic amino acids, propionate and glycerol are the major precursors for gluconeogenesis
LOCATION OF GLUCONEOGENESIS Gluconeogenesis occurs mainly in the cytosol. About 1 kg of glucose is produced everyday.
IMPORTANCE OF GLUCONEOGENESIS Glucose is a very key substance for the metabolism and its continuous supply is essential to the body for a variety of functions. Human brain alone requires about 120 g of glucose per day, out of 160 g needed by the entire body.
Glucose is the only source that supplies energy to the skeletal muscles under anaerobic conditions. Gluconeogenesis helps in clearing certain metabolites produced in the tissues, which accumulates in the blood. e.g. lactate, glycerol, propionate etc.
The degradation of glycogen in muscle results in the formation of lactate. Breakdown of fat in adipose tissue will produce free glycerol and propionate. Lactate, glycerol, propionate and some amino acids are good precursors for glucose synthesis. Gluconeogenesis continuously add glucose to the blood. Cori cycle is responsible for the conversion of muscle lactate to glucose in liver.
REACTIONS OF GLUCONEOGENESIS Gluconeogenesis closely resembles the reversed pathway of glycolysis. In glycolysis all the reactions, except three are reversible. These includes, Pyruvate to Phosphoenol Pyruvate Fructose 1,6 bisphosphate to Fructose 6 phosphate Glucose 6 phosphate to glucose
gluconeogenesis.pptx
Conversion of Pyruvate to Phosphoenol Pyruvate This takes place in two steps Pyruvate carboxylase is a Step 1: biotin dependent mitochondrial enzymes that converts pyruvate to oxaloacetate in presence of ATP and CO2. Oxaloacetate is synthesized mitochondrial matrix. It has in the to be transported to the cytosol to be used in the gluconeogenesis.
membrane impermeability, cannot diffuse out of Due to the oxaloacetate mitochondria. The oxaloacetate is firstly converted into malate and then transported to the cytosol. Within the cytosol, the oxaloacetate is regenerated. Malate dehydrogenase is the enzyme helps in the reconversion of oxaloacetate.
In the cytosol, pyruvate carboxykinase the enzyme Phosphoenol converts oxaloacetate to phosphoenol pyruvate. Step 2: Conversion of fructose 1,6- bisphosphate to fructose 6-phosphate: the enzyme converts fructose 1,6-bisphosphatase fructose 1,6-bisphosphate to fructose 6-phosphate.
Step 3: Conversion of glucose 6 phosphate to glucose: enzyme glucose 6-phosphatase catalyses the conversion of glucose 6 phosphate to glucose
GLUCONEOGENESIS FROM AMINO ACIDS Glucose is synthesized from the Pyruvates and the intermediates of the citric acid cycle.
GLUCONEOGENESIS FRO M GLyCEROL On hydrolysis of fats in adipose tissue glycerol is obtained. Glycerol is converted to glycerol 3 phosphate by an enzyme glycerokinase. Dihydroxy acetone phosphate is formed from glycerol 3 phosphate , by an enzyme called glycerol 3 phosphate dehydrogenase. Dihydroxy acetone phosphate is an intermediates of Glycolysis which can be used for glucose production.
GLUCONEOGENESIS FRO M PROPIONAtE Three carbon propionyl CoA is produced by the oxidation of fatty acids and breakdown of some amino acids. Propionyl CoA Carboxylase acts in the presence of ATP and biotin and converts to Methyl Malonu Co A, which is then converted into Succinyl Co A, in presence of B 12 coenzyme. Succinyl Co A then enters gluconeogenesis via citric acid cycle.
GLUCONEOGENESIS FRO M LACTATE
GLUCONEOGENESIS FRO M LACTATE Any activity involving the muscles requires energy, which comes in the form of Adenosine triphosphate (ATP) once it is converted from glycogen through the processes of glycogenolysis and glycolysis. When there is a lack of an adequate oxygen supply, typically the result of any intense muscular activity such as running; energy is released through anaerobic metabolism.
GLUCONEOGENESIS FRO M LACTATE Lactate, produced through the lactic acid fermentation is absorbed by liver and converted back into pyruvate and then into glucose. This glucose can then be used to replenish the levels of glycogen via glycogenesis and in turn, provide ATP via glycolysis once the muscular activity has ceased.Is called gluconeogenesis.
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gluconeogenesis.pptx

  • 1. Amoud medical school GLUCONEOGENESIS Dr. Mukhtar Jama Nour , MBBS, MD
  • 2. INTRODUCTION The production of glucose from non carbohydrate compounds is known as gluconeogenesis. Lactate, pyruvate, glucogenic amino acids, propionate and glycerol are the major precursors for gluconeogenesis
  • 3. LOCATION OF GLUCONEOGENESIS Gluconeogenesis occurs mainly in the cytosol. About 1 kg of glucose is produced everyday.
  • 4. IMPORTANCE OF GLUCONEOGENESIS Glucose is a very key substance for the metabolism and its continuous supply is essential to the body for a variety of functions. Human brain alone requires about 120 g of glucose per day, out of 160 g needed by the entire body.
  • 5. Glucose is the only source that supplies energy to the skeletal muscles under anaerobic conditions. Gluconeogenesis helps in clearing certain metabolites produced in the tissues, which accumulates in the blood. e.g. lactate, glycerol, propionate etc.
  • 6. The degradation of glycogen in muscle results in the formation of lactate. Breakdown of fat in adipose tissue will produce free glycerol and propionate. Lactate, glycerol, propionate and some amino acids are good precursors for glucose synthesis. Gluconeogenesis continuously add glucose to the blood. Cori cycle is responsible for the conversion of muscle lactate to glucose in liver.
  • 7. REACTIONS OF GLUCONEOGENESIS Gluconeogenesis closely resembles the reversed pathway of glycolysis. In glycolysis all the reactions, except three are reversible. These includes, Pyruvate to Phosphoenol Pyruvate Fructose 1,6 bisphosphate to Fructose 6 phosphate Glucose 6 phosphate to glucose
  • 9. Conversion of Pyruvate to Phosphoenol Pyruvate This takes place in two steps Pyruvate carboxylase is a Step 1: biotin dependent mitochondrial enzymes that converts pyruvate to oxaloacetate in presence of ATP and CO2. Oxaloacetate is synthesized mitochondrial matrix. It has in the to be transported to the cytosol to be used in the gluconeogenesis.
  • 10. membrane impermeability, cannot diffuse out of Due to the oxaloacetate mitochondria. The oxaloacetate is firstly converted into malate and then transported to the cytosol. Within the cytosol, the oxaloacetate is regenerated. Malate dehydrogenase is the enzyme helps in the reconversion of oxaloacetate.
  • 11. In the cytosol, pyruvate carboxykinase the enzyme Phosphoenol converts oxaloacetate to phosphoenol pyruvate. Step 2: Conversion of fructose 1,6- bisphosphate to fructose 6-phosphate: the enzyme converts fructose 1,6-bisphosphatase fructose 1,6-bisphosphate to fructose 6-phosphate.
  • 12. Step 3: Conversion of glucose 6 phosphate to glucose: enzyme glucose 6-phosphatase catalyses the conversion of glucose 6 phosphate to glucose
  • 13. GLUCONEOGENESIS FROM AMINO ACIDS Glucose is synthesized from the Pyruvates and the intermediates of the citric acid cycle.
  • 14. GLUCONEOGENESIS FRO M GLyCEROL On hydrolysis of fats in adipose tissue glycerol is obtained. Glycerol is converted to glycerol 3 phosphate by an enzyme glycerokinase. Dihydroxy acetone phosphate is formed from glycerol 3 phosphate , by an enzyme called glycerol 3 phosphate dehydrogenase. Dihydroxy acetone phosphate is an intermediates of Glycolysis which can be used for glucose production.
  • 15. GLUCONEOGENESIS FRO M PROPIONAtE Three carbon propionyl CoA is produced by the oxidation of fatty acids and breakdown of some amino acids. Propionyl CoA Carboxylase acts in the presence of ATP and biotin and converts to Methyl Malonu Co A, which is then converted into Succinyl Co A, in presence of B 12 coenzyme. Succinyl Co A then enters gluconeogenesis via citric acid cycle.
  • 17. GLUCONEOGENESIS FRO M LACTATE Any activity involving the muscles requires energy, which comes in the form of Adenosine triphosphate (ATP) once it is converted from glycogen through the processes of glycogenolysis and glycolysis. When there is a lack of an adequate oxygen supply, typically the result of any intense muscular activity such as running; energy is released through anaerobic metabolism.
  • 18. GLUCONEOGENESIS FRO M LACTATE Lactate, produced through the lactic acid fermentation is absorbed by liver and converted back into pyruvate and then into glucose. This glucose can then be used to replenish the levels of glycogen via glycogenesis and in turn, provide ATP via glycolysis once the muscular activity has ceased.Is called gluconeogenesis.