Glycolysis Regulation Flashcards
aerobic conditions
pyruvate to acetyl-CoA to CO2
anaerobic conditions
reduction of pyruvate to lactate
if glycolysis goes to lactate it will not produce _
2 NADH; they are converted to 2 NAD+ in conversion of pyruvate to lactate
Pasteur Effect
more glucose is consumed under hypoxic conditions to reach same amount of ATP produced in anaerobic conditions (pyruvate –> CO2 yields 25 more ATPs)
RBC’s use _ glycolysis
anaerobic; no mitochondria
muscle fibers use _ glycolysis
anaerobic or aerobic
hexokinase is inhibited by _
glucose-6-phosphate
glucokinase is inhibited by _
fructose-6-phosphate
phosphofructokinase is activated by _
AMP
phosphofructokinase is inhibited by _
H+ (lactic acid buildup), ATP, and citrate
pyruvate kinase is activated by _
fructose-1,6-bisphosphate
pyruvate kinase is inhibited by _
ATP and alanine (transamination of pyruvate)
glucokinase is regulated by _
GKRP binding
committed step of glycolysis
phosphofructokinase converting F6P to F-1,6-BP
PFK hormonal activation
insulin will activate PFK in response to high glucose levels
insulin
secreted by pancreatic beta-cells in response to high blood glucose; decreases [glucose] in circulation
glucagon
secreted by pancreatic alpha-cells in response to low blood glucose; increase [glucose] in circulation
F-2,6-BP
allosteric activator of PFK
synthesis of F-2,6-BP
bifunctional enzyme that acts as both a kinase (PFK-2) and phosphatase (FBPase-2)
glucagon on bifunctional enzyme
phosphorylates bifunctional enzyme to activate the phosphatase –> converts F2,6BP back to F6P to decrease F2,6P to slow glycolysis down (no PFK)
insulin on bifunctional enzyme
will dephosphorylate bifunctional enzyme to convert F6P to F26P for PFK activation (increase glycolysis)
How does glucagon phosphorylate Binfunc E?
binds a GPCR –> adenylyl cyclase –> cAMP –> PKA –> FBPase2 –> decrease F26BP
phosphorylation of pyruvate kinase
inactivates the enzyme; will be phosphorylated in presence of glucagon
insulin _ PKA
inhibits it to prevent it from phosphorylating stuff
insulin activates _
pyruvate kinase, glucokinase, and phosphofructokinase
glucagon inhibits _
glucokinase, phosphofructokinase, and pyruvate kinase
type I diabetes
no insulin due to pancreatic dysfunction; results in decreased glucose uptake (high blood glucose) which leads to malnutrition and wasting
type II diabetes
insulin resistance brought on by obesity; decreases glucose uptake resulting in high blood glucose
lactic acidosis
increase blood [lactate] which decreases blood pH; can be a symptom of circulatory/pulmonary failure, shock, convulsions
glycolytic enzyme deficiency
result in hemolytic anemia
