xxii
====
14 527
Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway
14.1 Glycolysis 528
528
An Overview: Glycolysis Has Two Phases
531
The Preparatory Phase of Glycolysis Requires ATP
535
The Payoff Phase of Glycolysis Yields ATP and NADH
538
The Overall Balance Sheet Shows a Net Gain of ATP
539
Glycolysis Is under Tight Regulation
539
Glucose Uptake Is Deficient in Type I Diabetes Mellitus
14.2 543
Feeder Pathways for Glycolysis
14.3 546
Fates of Pyruvate under Anaerobic Conditions: Fermentation
14.4 551
Gluconeogenesis
553
Conversion of Pyruvate to Phosphoenolpyruvate Requires Two Exergonic Reactions
556
Conversion of Fructose 1,6-Biphosphate to Fructose 6-Phosphate Is the Second Bypass
556
Conversion of Glucose 6-Phosphate to Glucose Is the Third Bypass
556
Gluconeogenesis Is Energetically Expensive, but Essential
557
Citric Acid Cycle Intermediates and Some Amino Acids Are Glucogenic
557
Mammals Cannot Convert Fatty Acids to Glucose
557
Glycolysis and Gluconeogenesis Are Reciprocally Regulated
14.5 558
Pentose Phosphate Pathway of Glucose Oxidation
559
The Oxidative Phase Produces Pentose Phosphates and NADPH
560
The Nonoxidative Phase Recycles Pentose Phosphates to Glucose 6-Phosphate
563
Wernicke-Korsakoff Syndrome Is Exacerbated by a Defect in Transketolase
563
Glucose 6-Phosphate Is Partitioned between Glycolysis and the Pentose Phosphate Pathway
====
15 569
Principles of Metabolic Regulation
15.1 570
Regulation of Metabolic Pathways
15.2 577
Analysis of Metabolic Control
15.3 582
Goordinated Regulation of Glycolysis and Gluconeogenesis
583
Hexokinase Isozymes of Muscle and Liver Are Affected Differently by Their Product, Glucose 6-Phosphate
585
Hexokinase IV (Glucokinase) and Glucose 6-Phosphatase Are Transcriptionally Regulated
585
Phosphofructokinase-1 and Fructose 1,6-bisphosphatase Are Reciprocally Regulated
587
Fructose 2,6-Bisphosphate Is a Potent Allosteric Regulator of PFK-1 and FBPase-I
588
Xylulose 5-Phosphate Is a Key Regulator of Carbohydrate and Fat Metabolism
588
The Glycolytic Enzyme Pyruvate Kinase Is Allosterically Inhibited by ATP
590
The Gluconeogenic Conversion of Pyruvate to Phosphoenol Pyruvate Is Under Multiple Types of Regulation
590
Transcriptional Regulation of Glycolysis and Gluconeogenesis Changes the Number of Enzyme Molecules
15.4 594
The Metabolism of Glycogen in Animals
595
Glycogen Breakdown Is Catalyzed by Glycogen Phosphorylase
596
Glucose 1-Phosphate Can Enter Glycolysis or, in Liver, Replenish Blood Glucose
596
The Sugar Nucleotide UDP-Glucose Donates Glucose for Glycogen Synthesis
601
Glycogenin Primes the Initial Sugar Residues in Glycogen
15.5 602
Coordinated Regulation of Glycogen Synthesis and Breakdown
603
Glycogen Phosphorylase Is Regulated Allosterically and Hormonally
605
Glycogen Synthase Is Also Regulated by Phosphorylation and Dephosphorylation
606
Glycogne Synthase Kinase 3 Mediates Some of the Actions of Insulin
606
Phosphoprotein Phosphatase 1 Is Central to Glycogen Metabolism
606
Allosteric and Hormonal Signals Coordinate Carbohydrate Metabolism Globally
608
Carbohydrate and Lipid Metabolism Are Integrated by Hormonal and Allosteric Mechanisms
====
16 615
The Citric Acid Cycle
16.1 616
Production of Acetyl-CoA (Activated Acetate)
616
Pyruvate Is Oxidized to Acetyl-CoA and CO2
617
The Pyruvate Dehydrogenase Complex Requires Five Coenzymes
618
The Pyruvate Dehydrogenase Complex Consists of Three Distinct Enzymes
619
In Substrate Channeling, Intermediates Never Leave the Enzyme Surface
16.2 620
The Citric Acid Cycle Has Eight Steps
630
The Energy of Oxidations in the Cycle Is Efficiently Conserved
631
Why Is the Oxidation of Acetate So Complicated?
631
Citric Acid Cycle Components Are Important Biosynthetic Intermediates
631
Anaplerotic Reactions Replenish Citric Acid Cycle Intermediates
633
Biotin in Pyruvate Carboxylase Carries CO2 Groups
16.3 635
Regulation of the Citric Acid Cycle
635
Production of Acetyl-CoA by the Pyruvate Dehydrogenase Complex Is Regulated by Allosteric and Covalent Mechanisms
636
The Citric Acid Cycle Is Regulated at Its Three Exergonic Steps
637
Substrate Channeling through Multienzyme Complexes May Occur in the Citric Acid Cycle
637
Some Mutations in Enzymes of the Citric Acid Cycle Lead to Cancer
16.4 638
The Glyoxylate Cycle Produces Four-Carbon Compounds from Acetate
639
The Citric Acid and Glyoxylate Cycles Are Coordinately Regulated
====
18 673
Amino Acid Oxidation and the Production of Urea
18.1 674
Metabolic Fates of Amino Groups
674
Dietary Protein Is Enzymatically Degraded to Amino Acids
677
Pyridoxal Phosphate Participates in the Transfer of alpha-Amino Groups to alpha-Ketoglutarate
677
Glutamate Releases Its Amino Group As Ammonia in the Liver
Box 18-1 678
Medicine: Assays for Tissue Damage
680
Glutamine Transports Ammonia in the Bloodstream
681
Alanine Transports Ammonia from Skeletal Muscles to the Liver
681
Ammonia Is Toxic to Animals
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