BC2002 lecture 7

Glycogen catabolism

the most significant “feeder pathway” into glycolysis

catabolized, monosaccharides, disaccharides

Carbohydrates besides glucose feed into glycolysis to be ______ including _____ (like fructose, galactose and mannose) and ______ (like sucrose, lactose, trehalose and maltose)

glycogen and starch

the most significant contributors are the storage polysaccharides ______

the cori’s

made major discoveries on glycogen metabolism between 1925-50 (nobel prize in 1947)

very large polymer of glucose in (α-1-4) and α-1-6) linkage

structure of glycogen particle

the structure has 12 tiers in the mature one with 55,000 glucose residues “build” on glycogenin protein

Large “α-rosettes” of glycogen granules

20-40 glycogen particles come together to form _____

glycogen

synthesized and stored in animal tissues and in microorganism

glucose

glycogen is readily mobilized storage formed of

stored, “metered out”

glycogen is _____bduring meals _____ during day

blood (glucose)

glycogen is important in maintaining constant

liver and skeletal muscle

in animal glycogen is primarily stored in the ______ but also in other cell types

liver

in the _____ glycogen is the glucose “reservoir” that supplies glucose to blood/tissues when dietary glucose low between meals/fasting we store enough for a day

skeletal muscle

in _____ glycogen is the glucose quick source of energy used up in under an hour during vigorous activity

Glycogen phosphorylase (GP)

main catabolic enzyme very highly regulated

phosphorylysis

glycogen phosphorylase (GP) sequentially removes terminal glucose residues from non-reducing end by

Glucose-1-phosphate

glycogen phosphorylase’s reaction adds phosphoryl group onto the terminal glucose to form _________ and “lyse” it off glycogen creates a lot of it

α-1–>6, 4 glucose

glycogen phosphorylase acts repetitively until it meets _____ beach stops working ______ residues before branch

transferase activity

the ____ of “debranching enzyme” removes 3 glucose residues before branch to another tier

(α1-6) glucosidase activity

the _________ of “debranching enzyme” cuts off glucose

glucose 1-phosphate

glycogen catabolism the outcome in liver and muscle cells, finally ends up with lots of _________ and phosphoglucomutase converts it to glucose 6-phosphate

liver

glucose 6-phosphate in the ______ turns into glucose in blood, which transports tissue which need it in glycolysis so so its used as energy

muscle

glucose 6-phosphate in the _______, helps in glycolysis step 2 (anaerobic/aerobic), used as energy

glycogen storage disease

Affects enzymes degrading and synthesizing glycogen

glycogen storage disease

it is rare and usually inherited in autosomal recessive manner, tested for at birth

enlarged, myopathy, metabolic

glycogen storage disease results in ______ liver, muscle wasting (______), _______ problems

low, carbohydrate

the treatment for glycogen storage diseases is a very _____ glucose and monitored ______ diet

phosphorylase, debranching enzyme, 6 phosphatase

glycogen storage diseases deficiencies: genetic mutations occur in glycogen _______, glycogen _____ _____, glucose _______