What is the major enzyme involved in GNG vs. glycolsis regulation? (4) List all points 2, 3, 3, 3
Describe what happens under fasting conditions and post-prandial conditions
PFK-1 (fructose <--> F1,6BP)
1. ATP:AMP ratio
(high ATP allosterically inhibits PFK, lowering PFK's affinity for F6P; low ATP:AMP ratio reverses inhibition)
2. High [H+] - inhibits PFK to prevent lactic acid buildup.
: high [citrate] inhibits PFK, indicating an abundance of precursor
4. FRUCTOSE 2,6 BP
- potent allosteric activator of pFK, increases PFK affinity for F6P, diminishes ATP inhibition (overrides most other activators)
1. Glucagon: (1) low blood glucose --> (2) Glucagon released from a-cells (3) binds to glucagon receptor (4) activation of G protein (5) activation of adenylate cyclase --> (6) activation of cAMP (7) activation of PKA (8) P'lases bifunctional enzyme (9) PFK-2 turned off, FBPase2 turned on (10) F2,6BP (PFK activator)--> F6P, no allosteric activator of PFK!!!
2. Insulin: (1) High blood glucose (2) insulin released from b-cells (3) binds to IR (4) destroys cAMP and releases PP (5) PP dep'lates bifunctional enzyme (6) FBPase 2 turned off, PFK2 turned on (7) PFK2 p'lates F6P --> F2,6BP (8) Activates PFK-1 for glycolysis.