Term
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Definition
-alternative source of glucose for energy production
-partial reversal of glycolysis
-occurs in liver and kidney
-starts in mitochondria, rest occurs in the cytosol
-provides glucose for tissues during prolonged fasting and starvation
-3 irreversible rxns are bypassed by 4 alternate rxns |
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Term
| gluconeogenesis substrates |
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Definition
-intermediates of TCA cycle and glycolysis-pyruvate, lactate, oxaloacetate
-products of triglyceride metabolism-glycerol (converted to dihydroxyacetone phosphate)
-products of amino acid metabolism-hydrolysis of tissue proteins and glucogenic amino acids |
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Term
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Definition
-carboxylation of pyruvate to form oxaloacetate (OAA)
-bypass of step 10
-enzyme-pyruvate carboxylase
-requires-biotin, ATP,CO2
-activated by acetyl CoA
-OAA is reduced to malate so it can cross membrane then reoxidized (requires NADH/NAD+) |
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Term
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Definition
-decarboxylation and phosphorylation of OAA to PEP
-enzyme-PEP-carboxykinase (PEPCK)
-driven by GTP hydrolysis
-combined with rxn 1, provides E favorable conversion of pyruvate to PEP |
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Term
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Definition
| -WelChol-inhibits PEPCK-prevents new glucose formation in liver |
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Term
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Definition
-dephosphorylation of fructose-1,6-bisphosphate to fructose-6-phosphate
-enzyme-fructose-1,6-bisphosphatase
-bypasses step 3
-inhibited by high AMP
-inhibited by fructose-2,6-bisphosphate |
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Term
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Definition
-dephosphorylation of glucose-6-phosphate to glucose
-bypass step 1
-enzyme-glucose-6-phophatase
-bypass of hexokinase rxn
-only in liver and kidney-skeletal muscle will not form or release free glucose |
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Term
| regulation of gluconeogenesis |
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Definition
-moment to moment control mainly by substrate availability
-slower long term control by hormones
-glucagon-activates it
-insulin-inhibits it |
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