Glucose Metabolism Flashcards
(26 cards)
Explain hexokinase…
Glucose –> G6P (glycolysis)
*present in all cells
Explain glucokinase…
Glucose –> G6P (glycolysis)
*present in liver, low affinity and high capacity for glucose
Explain PFK1…
F6P –> F-1,6-BP (glycolysis)
*Committed step
Explain phosphoglycerate kinase…
1,3-BPG –> 3-PG (glycolysis)
*creates an ATP
Explain pyruvate kinase…
PEP –> pyruvate (glycolysis)
*creates an ATP
Where do galactose and fructose enter glycolysis?
Galactose = G6P
Fructose (dietary) = DHAP/GAP
Fructose (fat) = F6P
How is pyruvate kinase activated/inactivated?
Phosphorylation = inactivated Dephosphorylation = activated
Where does High-Fructose Corn Syrup enter glycolysis?
DHAP
Explain pyruvate carboxylase…
Pyruvate –> oxaloacetate (gluconeogenesis)
Explain PEP carboxykinase…
Oxaloacetate –> PEP (gluconeogenesis)
Explain F-1,6-BPase…
F-1,6-BP –> F6P (gluconeogenesis)
Explain G6Pase…
G6P –> Glucose (gluconeogenesis)
Explain G6P dehydrogenase…
G6P –> Ribulose-5-phosphate (pentose phosphate)
- Rate limiting and oxidative step
- Creates 2 NADPH
Explain phosphoglucomutase…
G6P –> G1P (glycogenesis)
Explain UDP-glucose pyrophosphorylase…
G1P + UDP –> UDP-glucose (glycogenesis)
Explain glycogen synthase…
UDP-glucose –> existing glycogen chain (glycogenesis)
- Rate limiting step
- via alpha-1,4 bonds
Explain glycosyl transferase…
Adds ~7 UDP-glucose residues to glycogen chain as a branch via alpha-1,6 bonds
Explain glycogen phosphorylase…
Glycogen chain –> G1P residues
*Rate limiting step
Explain the debranching enzyme…
~3 residues of glycogen branch –> glycogen main chain
Then cleaves alpha-1,6 bond of final G1P residue
Explain the difference in G6Pase function in the liver VS the muscle…
Liver - creates free glucose to enter circulation
Muscle - creates glucose to enter glycolysis
What activates PKB?
Insulin binding to RTK on membrane
How does PKB function?
Sends waiting GLUT4 to membrane.
Phosphorylates/Activates PP1.
How does PP1 function?
Dephosphorylates/Inactivates glycogen phosphorylase.
Dephosphorylates/Activates glycogen synthase.
What activates PKA?
Glucagon binding to GPCR on membrane
