BC 26 Glycolysis 2

Question 1

Phosphofructokinase Regulation of Glycolysis

Answer 1

Rate limiting step of glycolysis

Phosphorylates Fructose 6 phosphate to Fructose 1,6 bisphosphate (for continuation of glycolysis)

activated by present of fructose 2,6 bisphosphate

increased IG ratio decreases cAMP and decreases protein kinase A -> dephosphorylation of PFK2(/FBP2)(bifxnl enz)
-dephos PFK2 = ACTIVE

PFK2 changes fructose 6 phosphate (product of original enzyme-phosphofructokinase) to F2,6bP

that activates phosphofructokinase

RULE OF THUMB, dephos state = active

Question 2

Pyruvate Kinase

Answer 2

Drives step 10 in glycolysis from phosphoenol pyruvate to pyruvate

enzyme further propelled by feed forward activation from F1,6bP (result of Phosphofructokinase1)

meaning: increased IG (dephos) drives glycolysis further here as well

Question 3

high protein low carb diet

Answer 3

keeping IG ratio low

decreases transcription of regulatory enzymes for glycolysis

body cannot handle sudden amounts of glucose for trapping and catabolism

GLucose tolerance test: appear hyperglycemic and diabetic

Question 4

Lactic Acidosis

Answer 4

Circulatory system collapses due to MI or Pulm Emb

decrease O2 availability

• decreases mito ATP increasing AMP
• increase AMPK activity increasing F2,6bP and PFK1

-all lead to increased glycolysis

HOWEVER, no mito ATP so all pyruvate shunted to Lactate leading to lactic acidosis

-bad but might be enough to keep tissue alive with ATP until fixed

Question 5

Two paths for NADH to get into Mito

Answer 5

1. donate electron to DHAP->Glycerol 3P
   -glycerol 3P diffuses into mito
   glycerol 3P donates e to FAD-> FADH
   (2ATP/NADH)
2. donate e to Oxaloacetate->malate
   -malate diffuses into mito
   malate donates e to NAD-> NADH and Oxaloacetate
   -OA exits the mito as aspartate via transaminase