BCCB2000 Lecture Notes - Lecture 17: Triose, Alanine, Cori Cycle
22 Jun 2018
School
Department
Course
Professor
Gluconeogenesis
Dr Steven Bottomley
Energy Stores in the Human Body:
Gluconeogenesis:
-Gluco glucose; neo new; genesis formation
-Synthesis of glucose from non-carbohydrate precursors
-Source of glucose
oMaintain blood glucose
Especially for tissues that prefer glucose or can only process
glucose e.g. brain, RBCs, kidney medulla, and testes
In starvation
During prolonged exercise
In normal homeostasis
oSource of glucose for other biomolecules e.g. polysaccharides,
glycolipids, glycoproteins
oGluconeogenesis generates 160g glucose per day for the whole body of
which 120g is for the brain
Pathway:
-Gluconeogenesis pathway
find more resources at oneclass.com
find more resources at oneclass.com
oConverts pyruvate into glucose
oMain precursors for pathway are
Lactate
Amino acids (alanine and glutamine)
Glycerol
oOccurs predominantly in liver and kidney cortex
-Gluconeogenesis is not complete reversal of glycolysis
oThree irreversible reactions of glycolysis
Glucose to glucose-6-phosphate
Fructose-6-phosphate to fructose 1,6 biphosphate
Phosphoenolpyruvate to pyruvate
oFour different gluconeogenic reactions ‘circumvent’ the three
irreversible reactions
find more resources at oneclass.com
find more resources at oneclass.com
Gluconeogenic Precursors:
-No-carbohydrate precursors
-Alanine and other glucogenic amino acids as sources of pyruvate
oFrom muscle
oAmino acids classified as glucogenic
-Glycerol as source of triose phosphate
oAdipose tissue
-Lactate as a source of pyruvate
oMuscle
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Gluco glucose; neo new; genesis formation. Source of glucose: maintain blood glucose. Especially for tissues that prefer glucose or can only process glucose e. g. brain, rbcs, kidney medulla, and testes. In normal homeostasis: source of glucose for other biomolecules e. g. polysaccharides, glycolipids, glycoproteins, gluconeogenesis generates 160g glucose per day for the whole body of which 120g is for the brain. Gluconeogenesis pathway: converts pyruvate into glucose, main precursors for pathway are. Glycerol: occurs predominantly in liver and kidney cortex. Gluconeogenesis is not complete reversal of glycolysis: three irreversible reactions of glycolysis. Phosphoenolpyruvate to pyruvate: four different gluconeogenic reactions circumvent" the three irreversible reactions. Alanine and other glucogenic amino acids as sources of pyruvate: from muscle, amino acids classified as glucogenic. Glycerol as source of triose phosphate: adipose tissue. Lactate as a source of pyruvate: muscle, rbcs. All sources processed through: liver (90-95%) or, kidney (10-25%) If 2 mol lactate uses 6 mol atp. 160 mmol lactate uses ??? mmol atp.
