In glycogenolysis, or the breakdown of glycogen, chain shortening is accomplished by?
glycogen phosphorylase. Adds a phosphate resulting in the formation of glucose 1-phosphate.
breaking down glycogen to glucose
Branch removal requires what 2 enzymes? What does each do?
4:4 transferase activity-- transfers the outer 3 of 4 residues to another branch
1:6 glucosidase activity: removes the single remaining glucose as free glucose
Glucose 1-phosphate is reversibly converted to glucose 6-phosphate by what?
In the liver, glucose 6-phosphate is transported into the ER by ________ and converted into glucose by __________.
Transported by: Glucose 6-phosphate translocase
Converted by: glucose 6-phosphatase
Describe Von Gierke disease (Glu 6-P def) and Glu 6-P Translocase Deficiency
Affect liver and kidney, severe fasting hypoglycemia, progressive renal disease, growth retardation and delayed puberty.
A deficiency in lysosomal acid maltase leads to vacuolar glycogen accumulation storage disease called?
Describle McArdle Syndrome
Skeletal Muscle Glycogen Phosphorylase or Myophosphorylase deficiency.
Weakness or cramping, no rise in blood lactate during exercise, normal mental devo, relatively benign condition.
Impaired branching enzyme leads to what glycogen storage disease?
Type IV: Andersen's
Hormonal regulation: Glucagon promotes __________, while insulin promotes __________.
Glucagon (fasting/starvation): glycogenolysis
Glucagon binds its receptor which activates adenylyl cyclase resulting in accumulation of cAMP, which activates ____________, which in turn of phosphorylates ___________ and converts it to its active form. This phosphorylates _______ and converts it to its active form too! Leads to glycogen degradation.
Glucagon binds its receptor which activates adenylyl cyclase resulting in accumulation of cAMP, which activates cAMP dependent protein kinase, which in turn phosphorylates glycogen phosphorylase kinase and converts it to its active form. This phosphorylates glycogen phoshorylase and converts it to its active form too! Leads to glycogen degradation,
Insulin activates protein phosphate-1, which dephosphorylates and returns ______ and _____ to their less active b forms.
glycogen phosphorylase kinase and glycogen phosphorylase.
______ binds to calmodulin subunit of phosphorylase kinase and activates it without phosphorylation.
Glycogenesis is inhibited by:
ATP and Glucose (inhibits glycogen phosphorylase a)
Glucagon-activated cAMP-dependent protein kinase A phosphorylates _______ converting it to its active form and allowing synthesis.
Insulin activates glycogen synthase via dephosphorylation by activating _________
Glycogenesis is promoted by high energy levels, i.e. _____
Glycogenolysis is promoted by:
low energy (AMP), epinephrine, or Calcium
During the fasting state, there is a decrease in blood glucose so a decrease in insulin release and an increase in glucagon release, which leads to increased protein kinase activity and _____________.
During the fasting state, there is a decrease in blood glucose so a decrease in insulin release and an increase in glucagon release, which leads to increased protein kinase activity and Glycogen phosphorylase.
___ signals low energy and allosterically activates glycogen phosphorylase b in the absence of its phosphorylation.
During the fed state, ingestion of glucose leads to increased blood glucose, which leads to release of insulin and decreased release of glucagon, which leads to protein phosphatase activity and ________!
During the fed state, ingestion of glucose leads to increased blood glucose, which leads to release of insulin and decreased release of glucagon, which leads to protein phosphatase activity and glycogen synthase!
Fructose occurs primarily with glucose as the disaccharide?
Galactose occurs primarily with glucose as?
Fructose and lactose do not promote secretion of insulin because they are
Cytoplasmic fructose is trapped mainly by fructokinase as __________.
How do you bypass traditional glycolytic control via phosphofructokinase-1? Cleave Fructose 1-Phosphate with ________ to create dihydroxyacetone and glyceraldehyde?
Recessive, absence of aldolase b, hypoglycemia, vomiting, jaundice, hepatomegaly, hepatic failure, and maybe death. Therapy= rapid detection & removal of fructose/sucrose from the diet.
Utilization of fructose is greatest in the ____, but rxns also occur in the kidney.
Lack of fructokinase, autosomal recessive, benign condition, and fructose accumulates in the liver.
What is a source of fructose and a sperm nutrient?
Excess sorbitol can occur under conditions of _________, which result in osmotic swelling, cataract formation, peripheral neuropathy, and microvascular swelling.
diabetes: high intracellular glucose
Mannose is trapped intracellularly by
Mannose 6-Phosphate can be isomerized by phosphomannose isomerase to?
Cytoplasmic galactose is phosphorylated to galactose 1-phosphate by
In galactose metabolism, an exchange rxn catalyzed by ______ yields UDP-galactose and glucose 1-phosphate.
galactose 1-phosphate uridyltransferase
Recessive, elevation of galactose in blood and urine, and causes galactitol accumulation if galactose is present in the diet.
Uridyltransferase deficiency, recessive, galactosemia, vomiting, diarrhea, jaundice, accumulation of galactose 1-phosphate and galactitol in nerves, lens, liver, etc. Liver damage, MR, and cataracts. Therapy: removal of galactose (lactose) from diet
Want to see the other 46 Flashcards in Glycogenesis, Glycogenolysis & Others 3-12?JOIN TODAY FOR FREE!