GLYCOGEN METABOLISM Flashcards
characteristics of G6P
Breaks down into pyruvate via glycolysis then breaks down into lactate or co2 + h2o
breaks down into g6p to go into the blood to be used by other tissues
breaks down into ribose + NADPH via the pentose phosphate pathway
enzymes that glycogen breakdown to
glycogen phosphorylase
glucosyl-4,4-transferase
alpha-1,6-glucosidase
regulating hormones of glycogen breakdown
insulin, glucagon, and epinephrine
degrades glycogen chains at their non-reducing end until 4 glucosyl units remain on each chain before the branch points
exoglycosidase
active form of phosphorylase, serine is phosphorylated by phosphorylase kinase in both subunits
phosphorylase A
inactive form, all enzymes are in the inactive state, serine is not phosphorylated, active when AMP is high and inactive when ATP and G6P are high, active only when energy is low in the muscle
Phosphorylase B
AMP independent
phosphorylase A
AMP dependent
Phosphorylase B
hormone that regulates liver glycogen
glucagon
what is liver phosphorylase allosterically regulated by?
glucose
catalyzes phosphorylation of glycogen synthase and inactivates it. also activates the glycogen phosphorylase
phosphorylase kinase
activators of protein kinase A
glucagon and epinepherine
initiates glycogenesis
glycogenin
catalyzes the formation of the glycosidic bond between c-1 of sugar and c-4 of accepting glucosyl residue
glycogen synthase
a glucose sensor, high blood glucose stops its own generation from glycogen breakdown, activated by PKA
glycogen phosphorylase
activates PKA
epinephrine
activates phosphatase 1,
insulin
glucose enters into the cell via what
GLUT 2
debranching enzyme deficiency-swollen abdomen, low blood sugar, high fat levels in blood and delayed growth
Cori
G6P deficiency, glucose going to the blood is inhibited, enlarged liver due to glycogen accumulation, can be treated with allopurinol
von gierke
a-1,4-glucosidase deficiency, glycogen accumulation in lysosomes leading to heart attacks from the disruptions in the myocardium
Pompe
branching enzyme dificiency, a-1,4 & 1,6-transflucosidase is missing, long chains build up causing cirrhosis and death
anderson
inability of muscle to use glycogen to regenerate ATP anaerobically, severe cramps and fatigue
mcardle
