Utilization Of Glucose- Lecture 9/16/21 Flashcards
Hexokinases
Phosphorylates glucose to keep it in the cell, found everywhere, low Km, inhibited by its product
Glucokinase
Found in the liver and pancreas beta cells, high Km so only active at high glucose concentrations, helps clear glucose from blood in the liver and stimulates insulin secretion in pancreas
Mechanism of insulin secretion
Production of ATP from glucose opens K+ channel, depolarizers the cell which causes Ca2+ to rush in causing insulin granules to fuse with membrane
3 regulated enzymes in glycolysis
Hexokinase, phosphofructokinase-1, pyruvate kinase
Relative levels of NAD+ to NADH in cell
NAD+»>NADH
Niacin (Vitamin B3)
Precursor to NADH
Reproduction of NAD+ in anaerobic conditions
Pyruvate reduced to lactate, NADH oxidized back to NAD+
Energy yield in anaerobic glycolysis
2 ATP
Key regulated enzyme of glycolysis (committed step)
Phosphofructokinase1 (PFK1)
Inhibitors of PFK1
ATP, and Citrate
Activators of PFK1
AMP, F2,6 bisphosphate
PFK2
Turns F6P to F2,6BP, when phosphorylated decreased glycolysis and when unphosphorylated increases glycolysis
NADPH
Produced by PPP, carries out reductions for example fatty acid synthesis
Glucose-6-phosphate dehydrogenase
Key regulated step in in PPP
Product of Oxidative PPP
NADPH
