wowa | weewa |
Gluconeogenesis | synthesis of glucose from pyruvate, lactate, amino acids and CAC intermediates and glycerol and Propionyl CoA. |
Gluconeogenis occurs | ONLY when there is an excess of energy |
Regulation | only one of either gluconeogenesis or glycolysis occurs at one given time |
Amt of glucose | is usually fairly constant |
Glucose stores | not enough for one day |
Liver | is the metabolic centre. Contains glycogen stores and gluconeogenesis occurs here. |
G6Pase | only foind in liver cells. (removes phosphate group and leaves glucose to be exported out of the liver. |
Synth glucose from pyruvate [1] | Pyruvate (3C) --> oxaloacetate (4C) PYRUVATE CARBOXYLASE
1ATP and CO2 required, carries a prosthetic group (biotin) |
Malate shuffle | to produce NADH (cytosol) and because there is no transporter for oxaloacetate out of mitochondria MALATE DEHYDROGENASE |
Glucose from pyruvate [1] | Oxaloacetate <--> phosphoenolpyruvate PEP CARBOXYKINASE
release of CO2; 1GTP required |
Pyruvate carboxylase on/off | ON high energy. OFF low energy |
HIGH Acetyl-CoA (control mechanism) | turns pyruvate carboxylase ON. turns pyruvate dehydrogenase OFF. |
Pyruvate carboxylase is | an anaplerotic enzyme. has the ability to top up levels of critical intermediates. |
Acetyl CoA control | decides whether oxaloacetate proceeds to GNG or CAC |
HIGH ATP, NADH or Acetyl CoA | oxaloacetate --> GNG |
LOW ATP | oxaloacetate --> CAC |
Glucose from pyruvate [2] | Fructose 1,6 Biphosphate --> Fructose 6 Phosphate FRUCTOSE 16 BIPHOSPHATASE. futile cycle: product is formed but can reverse and form reactant again. |
glucose from pyruvate [3] | Glucose 6 Phosphate --> Glucose GLUCOSE 6 PHOSPHATASE |
Regulatory enzymes | Pyruvate carboxylase, fructose 16 biphosphatase(turned on by high energy conditions and by hormonal control) |
GNG USES energy | 4ATP, 2GTP, 2NADH |
Glucose from lactate | lactate is sent to liver, converted to glucose and sent back to the muscles. LACTATE DEHYDROGENASE (lactate --> pyruvate in liver) |
synthesis of GLYCOGEN | Glycogen synthase... |
Glycogen synthase | utilizes UDP-glucose as one substrate and the non-reducing end of glycogen as another. The activation of glucose to be used for glycogen synthesis is carried out by the enzyme UDP-glucose pyrophosphorylase |
Glycogen is | highly branched to allow for fast mobilisation |
Glycogen is synthesized | at the non-reducing end. breakdown is also from the non-reducing end |
Glycogenin | begins synthesis. synthesises at least a tetrasaccharide then glycogen synthase takes over. |
SDL4 | check it |
Biosynthesis of lipods | Acetyl CoA -> Malonyl CoA -> FAs |
Acetyl CoA + CO2 using Acetyl CoA carboxylase | Malonyl CoA |
Acetyl CoA has biotin carrier | that acts as a cofactor to carry CO2 |
NADPH | reducing power to allow reaction |
Sources of Acetyl CoA | from carbs or protein breakdown THEREFORE excess carbs and proteins converted to fat |
Synthesis of FA occus | in the cytosol, therefore Acetyl CoA needs to be transported via citrate to cytosol |
Malonyl CoA inhibit | carnatine transporters so as to prevent FA degradation |
Ketone bodies | provide CoA that can be used as energy but are not preferred over glucose |
Starvation | check yellow book |