Carbs IV Flashcards
Where is glycogen synthesis performed?
muscle and liver
What is the difference between storage location of glycogen?
muscle = stores only for muscle
liver = stores for entire body
What is the function of UDP-glucose pyrophosphorylase?
to form UDP-glucose from UTP and G1P
What is the function of phosphoglucomutase?
G6P to G1P
Glycogen phosphorylase releases glucose molecules from glycogen in what form?
G1P
Is de-branching enzyme efficient?
one glucose is lost as G1P due to alpha-glucosidase activity
What product inhibits the activity of hexokinase?
G6P
What is the difference between muscle and liver in response to glucagon stimulation?
muscles do not possess glucagon receptors
What other property of muscles contributes to their inability to respond to glucagon?
muscles do not possess glucose-6-phosphatase
What is the difference between muscle and liver and their glycogenolysis reactions in response to epinephrine?
epinephrine causes the liver the breakdown glycogen
epinephrine causes the muscle to breakdown glycogen and to also increase glycolysis
What are the effetcs of PKA on glycogen synthase?
glycogen synthase is inactivated by PKA
What do patients with a glycogen storage disease usually present with?
muscle weakness/exercise intolerance
enlarged liver
What defect is present in Van Gierke Disease? (type I)
defect in glucose-6-phosphatase
What defect is present in Pompe Disease? (type II)
alpha-glucosidase deficiency
lysosomes fill with glycogen
What defect is present in Cori diease? (type III)
glycogen debranching enzyme
What defect is present in McArdle? (type V)
glycogen phosphorylase
What can MEOS do other than oxidize alcohol?
oxidize NADPH
What does heavy alcohol consumption induce?
MEOS
When NADH is high, what two metabolic intermediates disappear?
pyruvate and OAA
What two enzymes contribute to the disappearance of pyruvate and OAA?
lactate dehydrogenase and malate dehydrogenase
In general, what two major metabolic pathways are inhibited by NADH?
citric acid cycle and gluconeogenesis
What enzyme converts G1P into UDP-glucose?
UDP-glucose-pyrophosphorylase
Are hexokinase and glucokinase stimulated or inhibited by insulin?
both are stimulated
What is the difference in phosphorylation states between glycogen phosphorylase and glycogen synthase?
synthase = active when de-phosphorylated
phosphorylase = active when phosphorylated
