Glycolysis Flashcards
ATP yielded in glycolysis per glucose molecule (Malate-aspartate shuttle)
32
ATP yielded in glycolysis per glucose molecule (G3P shuttle)
30
Generally which cells use Malate-aspartate shuttle
Heart
Liver
Kidney
Generally which cells use G3P shuttle
Brain
other Muscle cells
Basal glucose uptake by which receptors
GLUT-1
GLUT-3
GLUT-1
RBC, endothelium of BBB
GLUT-2
Hepatocytes, pancreatic beta cells
GLUT-3
neurons
GLUT-4
skeletal muscle
adipose tissue
4 limbs have muscle and fat
GLUT-5
fructose transporter
GIT (jejunum)
sperm
Glucokinase found where
liver
pancreatic beta cells
Enzyme kinetics of glucokinase:
high Km –> requires high substrate concentration to reach higher velocity
high Vmax –> high velocity
Enzyme kinetics of hexokinase:
low Km, high affinity for glucose –> reacts with glucose easily, works at low glucose levels
RLE of glycolysis
PFK-1
Inhibits PFK-1
high ATP
citrate
Induces PFK-1
high AMP
F2,6BP
Net ATP of glycolysis
+2
ATP required for glycolysis
2
yields 2 ATP per half of glucose molecule or 4 ATP for net of +2
Stimulates pyruvate kinase
low Fructose-1,6BP
Inhibits pyruvate kinase
high ATP
alanine
Most common glycolytic enzyme deficiency
pyruvate kinase deficiency
Muscle biopsy of patient:
elevated glycogen levels
elevated F6P
decreased pyruvate
Deficiency of PFK-1
glucose not broken down but stored as glycogen
F6P not converted to F1,6BP –> high F6P
no downstream pyruvate
Glycolysis regulation: enzyme stimulated by fasting
Enzyme stimulated by fed state
(fasting) Glucagon stimulates Fructose bisphosphatase-2
(fed) Insulin stimulates Phosphofructokinase-2
Protein kinase A phosphorylates which enzyme in glycolysis regulation?
FBP-2/PFK-2 complex
