GLUCONEOGENESISBiosynthesis of glucose 3 4 carbon noncarbohydrate precursorsEnzymes located in the cytosolGluconeogenic organsLiver Kidney cortexFates Catabolism by nervous tissue Utilization by skeletal muscles

GLUCONEOGENESISSUBSTRATES GLUCOGENIC AMINO ACIDSLACTATEGLYCEROLPROPIONATE

PRECURSORSGLUCOSEFructose 1,6 - bisphosphateDihydroxyacetone phosphateGlyceraldehyde 3 - phosphateGLYCEROLPYRUVATEGlycerol 3 - phosphatePhosphoenolpyruvateOxaloacetateALANINELACTATEOther amino acidsPROPIONATESUCCINYL-CoA

CORI CYCLESKELETAL MUSCLELIVERBLOODGLUCOSE2 PYRUVATE2 LACTATEGLUCOSE2 PYRUVATE2 LACTATE6 ATP2ATP

PYRUVATEOXALOACETATEPEPPYRUVATELACTATEOAA

GLUCOSE - ALANINE CYCLESKELETAL MUSCLELIVERBLOODGLUCOSE2 PYRUVATE2 ALANINEGLUCOSE2 PYRUVATE2 ALANINE6 ATP2ATP2NH22NH2UREA

2 OxaloacetateGlucose 6 - phosphateGLUCOSE2 PYRUVATEFructose 6 - phosphateFructose 1,6 - bisphosphatePhosphoenolpyruvateATPATPATPATP2GTP2ATP2ATP2NADH2NADH12H2OH2O3

BYPASS REACTIONS PYRUVATE to PHOSPHOENOLPYRUVATEPYRUVATE CARBOXYLASEGenerates OXALOACETATEMitochondrial matrixATP DependentBIOTIN dependentACETYL CoA positive allosteric activator

BYPASS REACTIONS PYRUVATE to PHOSPHOENOLPYRUVATE PHOSPHOENOLPYRUVATE CARBOXYKINASEDecarboxylation and phosphorylationCytosolReversibleGTP Dependent

PEP CARBOXYKINASECO2OXALOACETATEPHOSPHOENOLPYRUVATE

BYPASS REACTIONS FRUCTOSE 1,6 BISPHOSPHATE to FRUCTOSE 6 - PHOSPHATEFRUCTOSE 1,6 - BISPHOSPHATASELIVERKIDNEYSKELETAL MUSCLE

BYPASS REACTIONS GLUCOSE 6 PHOSPHATE to GLUCOSEGLUCOSE 6 - PHOSPHATASEIrreversibleHydrolysisEndoplasmic reticulum of the liverAbsent in the brain and skeletal muscleRequires Mg+

SUMMARY of REACTIONS

REACTANTSPRODUCTSPyruvate + CO2 + ATP +H2OOxaloacetate + ADP + PiOxaloacetate + GTPPhosphoenolpyruvate + GDPPhosphoenolpyruvate2 phosphoglycerate2 phosphoglycerate3 - phosphoglycerate3 phosphoglycerate + ATP1,3 bisphosphoglycerate1,3 bisphosphoglycerate + NADHGlyceraldehyde 3 PO4Glyceraldehyde 3 PO4Dihydroxyacetone PO4G3-P + DHAPFructose 1,6 bisphosphateFructose 1,6 bisphosphateFructose 6 phosphateFructose 6 phosphateGlucose 6 phosphateGlucose 6 phosphateGLUCOSE

a 14 glycosidic bonda (16)glycosidic bondGLYCOGEN

GLYCOGEN SYNTHESISGLYCOGENESISPhosphorylation of glucose Requires activated glucose UDP Glucose UDP Glu pyrophosphorylaseGLYCOGENIN 332 amino acids Self-glucosylating enzyme Glycogen primer

GLYCOGEN SYNTHASE ReactionOHOGLYCOGENINGLYCOGEN + 1O

GLYCOGEN SYNTHESIS UDP - GLUCOSE Glucose 1 - PO4GLUCOSE 6 PO4GLUCOSEATPADPUTPPPiGLYCOGEN(Glucose)n(Glucose)n +1HEXOKINASEUDP-Glc PYROPHOSPHORYLASEPHOSPHOGLUCOMUTASEGLYCOGEN SYNTHASE

BRANCH Formation a 1, 6 glycosidic bond Branching enzyme amylo 1,4 1,6 transglycosylase Transfers terminal residues 6 -7 residues

GLYCOGEN SYNTHESIS

GLYCOGEN DEGRADATIONGLYCOGENOLYSIS Phosphorolysis Requires inorganic phosphate a 1, 4 glycosidic bond Glucose 1 - phosphate

GLYCOGEN PHOSPHORYLASEHOGLYCOGENGLYCOGEN - 1HPO4

DEBRANCHING ENZYME

GLYCOGENOLYSISH2O

GLYCOGEN METABOLISMGlycogen breakdown requires the interplay of GLYCOGEN PHOSPHORYLASE, OLIGOTRANSFERASE, and a 1, 6 GLUCOSIDASEGlycogen is synthesized by a different pathway involving GLYCOGEN SYNTHASE and a BRANCHING ENZYME.SYNTHESIS and DEGRADATION are RECIPROCALLY REGULATED.

CARBOHYDRATES