glycogen storage
branching enzyme
- moves a block of oligoglucose from one chain and adds it to the growing glycogen as a new branch using and aplpha-1,6 glycosidic link
what does enzyme do muscles lack?
glucose-6-phosphatase
phosphorylation of glucose
glucose-6-pophate
pompe disease
- lysosomal alpha-1,4- glucosidase deficiency accumulation of glycogen in lysosomes, muscle hypertonia, death ,
glycogen
An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.
andersen disease
GSD - Type IV - Branching Enzyme glycogen with few branches less soluble liver cirrhosis, portal vein hypertension esophageal varices death
McArdle's disease
Muscle phosphorylase deficiency no lactate exercise induced cramping and pain, red urine
binding of glucagon to receptor
activation of PKA which phosphorylation the B FORM OF PHORPHRYLASE. INCREASE GLYCOGEN BREAKDOWN
when glucagon binds to hepatocytes it activates what
adenylate cyclase which increases cAMP and activate PKA
glycogen polymer of glucose residues linked by
alpha (1-4) and (1,6) glycosidic bonds
the activity of hexokinase in muscles means
any free glucose is immediately phosphorylated and enters the glycolytic pathway
what is the major site of daily glucose consumption
brain
glycogenolysis
breakdown of glycogen to glucose occurs by glycogen phosphorylase
released calcium bind what
calmodulin subunit of PhK and this reduces the activity of glycogen synthase
glycogenin
catalyzes its own glycosolation attaching c-1 or UDP glucose to tryosine residue of the enzyme
Epinephrine
cause glycogen break down
protein phosphatases
dephosphorylate glycogen synthase
acetylcoline
depolarize muscle cells and activation phosphorylase kinase
where does the body obtain glucose
diet or from amino acids and lactate via gluconeogenesis
glycogen storage disease
disorders resulting from defects ingenues encoding enzymes involved in process of glycogen synthesis or breakdown
glycogen synthase phosphorylase kinase
enzyme critical for regulation of the flux of glucose into and out of glycogen as it reciprocally regulates the 2 key enzymes of glycogenolysis and glycogen synthesis
Van Gierke disease
enzyme deficiency : glucose 6 phosphatase. increase glycogen accumulation in liver adrenal tubule cells, hypoglycemia, lactic academia ketosis,
what is a major sources of stored glucose
glycogen of skeletal muscle
PKA phosphorylates what
glycogen synthase
activation by G6P doesn't occur when
glycogen synthase is not pohsoprylated
insulin
increases the activity of glycogen synthase
glucagon
inhibits glycogen synthase
de novo glycogen synthesis
initiated by attachment of glucose residue to protein knows glycogen
phophoprotein phosphatase 1
lets it bind to PP1, and thus stops dephosporylating glycogen synthase
glocose 1 phosphate uridyltransferase
makes UDP glucose
udp glucose under going glycogen synthase
makes glycogen +1 glucose
phk
phophorylase kinase that regulate glycogen synthase activity
what influences activity of glycogen synthase?
phosphorylation of serine residues on subunit proteins. this reduces its activity to UDP glucose
glycogenin
protein with self-glycosylating activity that serves as the primer molecules for initiation of glycogen synthesis
debranching enzyme
removes oligosaccharides from a branch in glycogen or starch. can transfer glucose to new branch and then excise the first glucose in the branch as free glucose
glycogen pho
removes single glucose and have that glucose be phosphorylated. can't remove glucose residues rom branch points in glycogen
glycogen synthase
tetrameric enzyme, different in liver and muscle
glycogen synthase
utilizes UDP glucose as 1 substrate and nonreducing end of glycogen
does epinephrine cause the release of glucose from glycogen?
yes