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Lecture11powerpoint - Hormonal Control of CHO Metabolism...

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Unformatted text preview: Hormonal Control of CHO Metabolism and Fatty Acid Breakdown May 6, 2008 Major concepts from last time • Flux through metabolic pathways is controlled by regulating the activities of key physiologically irreversible enzymes (KPIE). • KPIEs are typically at beginning of pathways, or near committed steps within pathways. • Opposing pathways can function simultaneously, but not at the same rate (partial futile cycling). • Partial futile cycling allows two points of control to achieve greater changes in flux (down-regulate and up-regulate KPIEs). • Allostery and covalent modification regulate activities of KPIEs and in the case of CM, also the NZs that catalyze the modification and/or de-mod.! 2 C Active Protein Kinase A AKA active cAMP-dep Protein Kinase (a serine/threonine kinase) Phosphorylase b kinase less active form Phosphorylase b kinase more active phosphorylated form ATP ADP ATP ADP ATP ADP ATP ADP Phosphorylase b less active form Phosphorylase a more active phosphorylated form Glycogen synthase I more active form glucose-6-P indep. Glycogen synthase D less active , phosphoryl. form glucose-6-P dep. High rate of Glycogen breakdown Slow rate of Glycogen breakdown H 2 O HPO 4 3- HPO 4 3- H 2 O Covalent Modification Regulates Mammalian Glycogen Metabolism in liver,muscle in liver,muscle Bifunctional PFK-2/F-2,6BPase more active/less active Bifunctional PFK-2/F-2,6BPase less active/more active in liver only ATP ADP Protein phosphatase inhibitor protein (PPIP) inactive b form Protein phosphatase inhibitor protein (PPIP) active a form H 2 O HPO 4 3- H 2 O HPO 4 3- H 2 O HPO 4 3- PP PP PP PP PP Slower rate of...
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This note was uploaded on 03/04/2010 for the course BIS 103 taught by Professor Abel during the Spring '08 term at UC Davis.

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Lecture11powerpoint - Hormonal Control of CHO Metabolism...

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