Lecture 8: Gluconeogenesis in Detail

Gluconeogenesis

The metabolic pathway that generates glucose from 3-carbon intermediates.

Phosphatase

An enzyme that removes phosphate groups from molecules.

Fructose 1,6-bisphosphatase

An enzyme involved in gluconeogenesis that converts fructose 1,6-bisphosphate to fructose 6-phosphate.

Glucose 6-phosphatase

An enzyme that converts glucose 6-phosphate to glucose, primarily in the liver.

Phosphoenolpyruvate (PEP) carboxykinase

An enzyme that converts oxaloacetate to phosphoenolpyruvate in gluconeogenesis.

Pyruvate carboxylase

An enzyme that converts pyruvate to oxaloacetate, crucial for gluconeogenesis.

Fructose 2,6-bisphosphate (F26BP)

A powerful regulator of glycolysis and gluconeogenesis.

Insulin

A hormone that promotes glycolysis by stimulating PFK-2 and inhibiting FBPase-2.

Glucagon

A hormone that stimulates gluconeogenesis by activating FBPase-2 and inhibiting PFK-2.

Pyruvate

A 3-carbon intermediate that serves as a key molecule in metabolic pathways.

Oxaloacetate

A 4-carbon molecule formed from pyruvate during gluconeogenesis.

Acetyl-CoA

A molecule that plays a key role in metabolism and stimulates pyruvate carboxylase.

Anaplerosis

The process of replenishing Krebs Cycle intermediates that have been used for biosynthesis.

Krebs Cycle

A series of metabolic reactions that generate energy through the oxidation of acetyl-CoA.

G6P transporter

A transporter that facilitates the movement of glucose 6-phosphate into the endoplasmic reticulum.

GLUT2

A glucose transporter that allows glucose to exit liver cells into the bloodstream.

Allosteric regulators

Molecules that bind to an enzyme at a site other than the active site, altering its activity.

ATP

A molecule that provides energy for many biochemical reactions, including gluconeogenesis.

ADP

A molecule that can activate glycolysis when ATP levels are low.

AMP

A molecule that indicates low energy and can promote gluconeogenesis.

Citrate

A molecule that negatively regulates PFK-1, inhibiting glycolysis.

Hexokinase

An enzyme that phosphorylates glucose, trapping it in the cell.

2-deoxy derivatives

Modified glucose molecules used in clinical diagnostics to trap glucose in cancer cells.

PET scan

A diagnostic imaging method that visualizes metabolic processes in the body.

Fatty acid oxidation

The metabolic process that breaks down fatty acids to produce acetyl-CoA.

Glycolysis

The metabolic pathway that breaks down glucose to produce energy.

Regulators

Substances that affect the activity of enzymes involved in metabolic pathways.

Dual identity of PFK/F26BPase

The ability of the same enzyme to function as both PFK and FBPase under different regulatory changes.

Glycolytic energy releasing steps

Key steps in glycolysis that release energy, which gluconeogenesis must bypass.

Equilibrium reactions

Reactions that can proceed in both directions without the need for additional enzymes.

Phosphorylation changes

Modifications to enzymes that can alter their activity, important for regulation.

Consequences of PFK/F26BPase changes

Changes in PFK and F26BPase activity can significantly affect cellular metabolism.