Lecture 26 Glycogen Synthesis-BW

Celluose dont have the enzyme that can break the beta

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Unformatted text preview: a 1,4 linkage. the c arbons involved are the same but linkage will make the difference - celluose hydroxyl group in the upward position. The type of linkage ( or ) determines the structure St a r c h c an get the nutrients from grasss - organ known as rumin - can break down the beta 1,4 glyocgic bond. some organisms ahve the ability to metabolism celluose - humans lack the enzyme. metabolize stratch. E n e r g y s t o r a ge 4/15/13 C e l l u lose St r u c t u r a l su p po r t MCB 2000 Lecture 26 have alpha 1,4 linages linear. at one branched point y ou will have an alpha 1,6. beyond 1,6 (branched only) all the rest will have 1,4 linkage. amylopectin and glyocgen only. glyocgen adopt this structure. aniamsl including human move a lot if an animal being chased by pepetor. - fl ight or fi ght r esponse advantage of having a branched stucture-allows for the breakdown of glyocgen at mult ends. to liberate the glucose molecule by the animal. branched stucture allows for rapid degratio and the relaese of glucose to deal with an emererngy situation. allows for some storage. water linked to glyocgen molecule. very polar. glyocgen Structure of Glycogen stored with water. Branched glucose polymer linked together by -1,4 glycosidic bonds and -1,6 glycosidic bonds at branch points. Beginning of chain is attached to a protein, glycogenin. Branched structure permits rapid synthesis and degradation from multiple reducing ends. G- important protein that build glyocgen s turcutre called glyocgeinin 4/15/13 Branched structure increases solubility. Synthesis of Glycogen When: Favored by high insulin/glucagon ratio Synthesis occurs in response to elevated blood glucose from a meal. How: Requirement for UTP in the activation step. Major enzyme: Glycogen synthase HIgh insulin to glcagon - forming covalent bonds - Oglycolsis linkage - covalent. - make a protein from amino acids. - need to do the same for glycogen - use UTP - use it as the activaition step - what is the activaition step for glycogen synthase? or fatty acid? or cholestoral? s ometimes use a nuecoltide- need to be aware of what the activaitoin step is. the reason you have an acitviation step is - not an exergonic - it is engeronic -require reducing equailivant. glycogen- have a lot of enzyme for glyolcysis - glyocgen syntahse. - major enzyme r egulated - 4/15/13 MCB 2000 Lecture 26 Synthesis of Glycogen: Reactions Glucose G-6-P G-6-P G-1-P (isomerization) G-1-P + UTP UDP-glucose Activation step Catalyzed by UDP-glucose pyrophosphorylase add phosphate - to trap glucose in the cell - conecntration gradient. c ould go into glycoysis - glyocgen s ynthesis - start with glucose 6 phosphate - move to number 1 position - isomerization - then gluocse 1 phosphate activate with UTP and end up UDP glucose. this is the activaition step glucose 1 phosphate plus UTP to get UDPglucsoe - every time you add a s ingel glucose molecule you need to carry out the activaiton step - not a one time only stpe - everytime y ou had a...
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