CHAPTER 16 GLYCOLYSIS

During glycolysis we will have a fragmentation of 6 Carbon atoms into a molecule of 3 Carbon atoms.

Glycolysis takes place in the cytosol.

Glycolysis is divided into two phases and 10 reactions occur.

The final balance of the glycolysis is the creation of 4 molecules of ATP, 2 of NADH and 2 of pyruvate with a single molecule of glucose.

Three reactions are regulated in glycolysis (1º, 3º and 10º)

First reaction: Glucose is phosphorylated into Glucose-6-Phosphate.

Sixth reaction: Glyceraldehyde is phosphorylated and oxydated into 1,3-Biphosphoglycerate.

Seventh reaction: 1,3-BPG transfer the phosphate group to a ATP forming 3-Phospoglycerate.

This enzyme does not act in glycolysis.

This enzyme acts in glycolysis but in any reaction here present.

Sixth reaction

Seventh reaction

Eighth reaction

Ninth reaction

Tenth reaction

Glucose -> Glucose 6-Phosphate -> Fructose 6-Phosphate -> Fructose 1,6 biphosphate -> Dihydroxyacetate phosphate -> Glyceraldehyde 3-Phosphate -> 1,3 Biphosphoglycerate -> 3-Phosphoglycerate -> 2-Phosphoglycerate -> Phosphenolpyruvate -> Pyruvate

Glucose -> Glucose 6-Phosphate ->Fructose 1,6 biphosphate -> Fructose 6-Phosphate -> Dihydroxyacetate phosphate -> Glyceraldehyde 3-Phosphate -> 1,3 Biphosphoglycerate -> 3-Phosphoglycerate -> 2-Phosphoglycerate -> Phosphenolpyruvate -> Pyruvate

Glucose -> Glucose 6-Phosphate -> Fructose 6-Phosphate -> Fructose 1,6 biphosphate -> hydroxyacetate diphosphate -> 1,3 Biphosphoglycerate -> 3-Phosphoglycerate -> 2-Phosphoglycerate -> Phosphenolpyruvate -> Pyruvate

Glucose -> Glucose 6-Phosphate -> Fructose 6-Phosphate -> Fructose 1,6 biphosphate -> Dihydroxyacetate phosphate -> Glyceraldehyde 3-Phosphate -> 3-Phosphoglycerate ->1,3 Biphosphoglycerate -> 2-Phosphoglycerate -> Phosphenolpyruvate -> Pyruvate

Glucose -> Glucose 6-Phosphate -> Fructose 6-Phosphate -> Fructose 1,6 biphosphate -> hydroxyacetate diphosphate -> Glyceraldehyde 3-Phosphate -> 1,3 Biphosphoglycerate -> 3-Phosphoglycerate -> 2-Phosphoglycerate -> Phosphenolpyruvate -> Pyruvate

Hexokinases I,II,III have a high specifity and a high affinity.

Glucokinase has a high specifity and a low affinity.

Hexokinases I,II,III are only present in liver.

Glucose-6-phosphate can inhibit glucokinase but can not do anything with hexokinase I,II and III.

In the phosphofructokinase the activators are F26BP, AMP and ATP

The energy charge increases

The energy charge is not affected and ADP and AMP are activators

ATP increases and it is an inhibitor

The energy charge decreases

The citrate concentration increases because it is an activator

When PKA phosphorylates the bifunctional enzyme that catalyses the transformation of F6P into F26BP synthesis of glucose is activated and glycolysis in inhibited.

When PKA phosphorylates the bifunctional enzyme that catalyses the transformation of F26BP into F6P synthesis of glucose is activated and glycolysis in activated.

When Adenylate cyclase phosphorylates the bifunctional enzyme that catalyses the transformation of F26BP into F6P synthesis of glucose is activated and glycolysis in inhibited.

When Adenylate cyclase phosphorylates the bifunctional enzyme that catalyses the transformation of F26BP into F6P synthesis of glucose is activated and glycolysis in activated.

When PKA phosphorylates the bifunctional enzyme that catalyses the transformation of F26BP into F6P synthesis of glucose is activated and glycolysis in inhibited.

Low Glu -> Glucagon -> High AMPc -> +PKA -> BEz is phosphorylated -> Low F26BP -> Glycolysis is blocked

High Glu -> Insulin -> Phosphatases -> Not phosphorylation of BEz -> High F26BP -> Glycolysis is activated

Low Glu -> Insulin -> High AMPc -> +PKA -> BEz is phosphorylated -> Low F26BP -> Glycolysis is blocked

High Glu -> Glucagon -> Phosphatases -> Not phosphorylation of BEz -> High F26BP -> Glycolysis is activated

High Glu -> Insulin -> Phosphatases -> Not phosphorylation of BEz -> Low F26BP -> Glycolysis is activated

Fermentation in absence of O2

Transform pyruvate into ethanol

Produce lactic acid

Act in the Krebs cycle

Transform pyruvate into fructose