Carbohydrate Metabolism

Catabolism ~15% ~85%

Central Role of Glucose

Fig 14-3 Fates of Pyruvate Fig 14-3

Two phases of glycolysis

Fig 14-2

Fig 14-2

Preparatory Phase Fig 14-2

Reaction 1: phosphorylation pg 526 pg 532

Reaction 2: isomerization pg 532

Fig 14-4

Reaction 3: phosphorylation pg 532

Reaction 4: cleavage pg 533

Reaction 5: isomerization pg 534

Fig 14-6

Fig 14-6

Fig 14-2

Reaction 6: oxidation pg 535

Covalent catalysis

Reaction 7: substrate level phosphorylation pg 536

Reaction 8: shift of phosphoryl group pg 537

Fig 14-8 ~Fig 14-8

Reaction 9: dehydration pg 538

Reaction 10: substrate level phosphorylation pg 538

Efficiency

Feeder Pathways Fig 14-9

Glycogen Breakdown

Glycogen Phosphorylase Breakdown Step 1. Glycogen Phosphorylase Fig 15-12 Pyridoxal phosphate

Glycogen Breakdown Phospho- glucomutase Fig 15-12 Fig 15-27

Glycogen Breakdown Debranching enzyme

Glycogen storage diseases

Case study Baby Sam was fine until 6 weeks of age but has not been thriving since her parents lengthened the time between feedings. She wakes frequently and is cranky but calms down with feeding. Her tummy is protruding more and more. It is obvious that she is suffering from hypoglycemia (and blood tests confirm this). What could be wrong, and what sorts of tests would you do to confirm your suspicions?

Fate of the products, pyruvate and NADH Fig 14-3

LDH reaction pg 547

Pyruvate decarboxylase reaction

Alcohol dehydrogenase reaction pg 547

Regulation of glycolysis Irreversible steps are regulated: Hexokinase/Glucokinase Phosphofructokinase I Pyruvate Kinase

Control of glycogen phosphorylase phosphorylation phosphorylase b (inactive) phosphorylase a (active) glycogen breakdown

Glycogen phosphorylase is activated upon phosphorylation by phosphorylase kinase.

Glycogen phosphorylase is activated upon phosphorylation by phosphorylase kinase. Phosphorylase kinase is activated upon phosphorylation by protein kinase A (PKA).

Glycogen phosphorylase is activated upon phosphorylation by phosphorylase kinase. Phosphorylase kinase is activated upon phosphorylation by protein kinase A (PKA). PKA is activated by cyclic AMP, which is produced by a G-protein in response to epinephrine/glucagon.

Fig 14-1

Key Enzyme: G6P Dehydrogenase Defect in G6P dehydrogenase leads to malarial resistance but can trigger hemolytic anemia.

Regulation G6P dehydrogenase is allosterically inhibited by NADPH; activated by NADP+