lecture_24legge

lecture_24legge - 11/13/2009 Gluconeogenesis...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
11/13/2009 1 Gluconeogenesis / TCA 11/12/2009 Gluconeogenesis Gluconeogenesis is the process whereby precursors such as lactate, pyruvate, glycerol, and amino acids are converted to glucose. Fasting requires all the glucose to be synthesized from these non-carbohydrate precursors. Most precursors must enter the Krebs cycle at some point to be converted to oxaloacetate. Oxaloacetate is the starting material for gluconeogenesis Overview of Glucose Metabolism The metabolic fate of pyruvate Free energy changes in glycolysis Reaction enzyme Δ G ° ´ Δ G ° 1 Hexokinase -20.9 -27.2 2 PGI +2.2 -1.4 3 PFK -17.2 -25.9 4 Aldolase +22.8 -5.9 5 TIM +7.9 +4.4 6+7 GAPDH+PGK -16.7 -1.1 8 PGM +4.7 -0.6 9 Enolase -3.2 -2.4 10 PK -23.3 -13.9
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
11/13/2009 2 Gluconeogenesis is not just the reverse of glycolysis Several steps are different so that control of one pathway does not inactivate the other. However many steps are the same. Three steps are different from glycolysis. 1 Pyruvate to PEP 2 Fructose 1,6- bisphosphate to Fructose-6- phosphate 3 Glucose-6-Phosphate to Glucose Gluconeogenesis versus Glycolysis Gluconeogenesis versus Glycolysis Pyruvate is converted to oxaloacetate before being changed to Phosphoenolpyruvate 1. Pyruvate carboxylase catalyses the ATP-driven formation of oxaloacetate from pyruvate and CO 2 2. PEP carboxykinase (PEPCK) concerts oxaloacetate to PEP that uses GTP as a phosphorylating agent.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 7

lecture_24legge - 11/13/2009 Gluconeogenesis...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online