BIOC 3300 Lecture Notes - Lecture 4: Phosphoenolpyruvate Carboxykinase, Glycogen Phosphorylase, Pyruvate Carboxylase
13 Jan 2016
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: phosphorolysis of -1,4-glycosidic linkages of the glycogen polymer: branching enzyme, conversion of pyruvate to phosphoenolpyruvate: - requires energy input and proceeds in two steps. Addition of co2 to pyruvate to produce oxaloacetate using atp by pyruvate carboxylase. Reaction occurs in the mitochondrial matrix (must be transported to cytosol for remaining steps). Phosphorylation and decarboxylation of oxaloacetate by pep carboxykinase (pepck) in presence of gtp. Investment of 2 high energy phosphates: debranching enzyme: It transfers a fragment of 6-7 glucose units from a length of at least 11 units to an interior glucose in 1,6 linkage: the change of [f26bp] on glycolysis and gluconeogenesis: Required to mobilize at branchpoints: dephosphorylation of fructose-1,6-bisphosphate: - catalysed by fructose-1,6-bisphosphatase. Not coupled to atp generation, pi is released. A major site of regulation of gluconeogenesis: dephosphorylation of glucose-6-phosphate: - catalysed by glucose-6-phosphatase in er. Not coupled to atp generation, pi is released: enzymes in mobilization of glycogen:
