After Digestion And Absorption Of Food What Next?

General Overview Of Metabolism (Carbohydrate, Protein, Fat)

Carbohydrate Chemistry and Metabolism By Gladys Kaba

Outline Carbohydrate chemistry Summary of digestion and absorption of carbohydrates. General overview of metabolism

Outline 4. Carbohydrate Metabolism Glycolysis TCA cycle Gluconeogenesis Metabolism of (Fructose, galactose, Mannose) PPP Glycogenesis and Glycogenolysis

After Digestion And Absorption Of Carbohydrates What Next? Carbohydrate Metabolism (Glucose)

We eat food containing carbohydrates

General Overview Of Metabolism (Carbohydrate, Protein, Fat)

Overview Of Carbohydrate Metabolism

(1) Glycolysis - Summary glycolysis occurs in the cytosol Glucose (6C) 2 ATP 4 ADP 2 ADP 4 ATP Location Of Glycolytic Enzymes? 2 NAD 2 NADH + H 2 Pyruvate (3C)

Functions/Importance Of Glycolysis Glycolysis Provides Energy Glycolysis Provides Substrate for Oxidation Intermediates Products are used in Other Pathways 2,3-bisphosphoglycerate, fatty acid and cholesterol synthesis Alanine, glycerol 3-phosphate

Cells With Special Needs Of Glycolysis Erythrocytes (Red blood cells) Lens and cornea of the eye Cells in brain cells

Physiological And Pathophysiological Conditions with special need for Glycolysis Fed State Exercising muscles Cancer cells-----Warburg effect

Phosphofructokinase-1 Fructose 6-phosphate Glucose Glucose 6-phosphate Phosphohexose isomerase Hexokinase Phosphofructokinase-1 Fructose 1,6- bisphosphate Pyruvate kinase Phosphoenolpyruvate Pyruvate 2-Phosphoglycerate Phosphoglycerate mutase Glyceraldehyde 3-phosphate dehydrogenase 1,3-Bisphosphoglycerate Phosphoglycerate kinase 3-Phosphoglycerate

Glycolysis Regulation

Abnormalities Associated with Glycolytic pathway   Affected Glycolytic enzyme/reaction Genetic Deficiencies of Glycolysis pyruvate kinase phosphoglycerate kinase

Toxin affecting Glycolytic pathway Mercury Arsenic

After Glycolysis What next after? Lactate (anaerobic) Glucose → 2 Pyruvate Acetyl-CoA (TCA cycle)

1. Conversion of pyruvate to Acetyl CoA aerobic conditions Location Of Pyruvate Dehydrogenase ?

Glycolysis cytoplasm Glucose Pyruvic acid Acetyl-CoA mitochondrion Kreb’s Cycle Glucose Glycolysis cytoplasm Pyruvic acid Acetyl-CoA mitochondrion Citric Acid Cycle Electron Transport ATP Production

Carbohydrate, protein, and Fat Metabolism

Kreb’s Cycle Aka Tricarboxylic Acid Cycle TCA Cycle Citric Acid Cycle Location Of Pyruvate Dehydrogenase And The TCA-cycle Enzymes?

Main Function of the Kreb’s cycle Oxidative process 3 NADH FADH2 GTP X 2 per glucose 6 NADH 2 FADH2 2 GTP All ultimately turned into ATP (oxidative phosphorylation/ electron transport chain)

Total Energy per glucose A) Cytosol Glycolysis 2 NADH 2 ATP B) Mitochondrion Pyruvate dehydrogenase --Krebs 6 NADH 2 FADH2 2 GTP

Abnormalities / Diseases Associated With PDH And The TCA Cycle Genetic Deficiency of Pyruvate Dehydrogenase 2) Genetic Diseases of the TCA Cycle : Fumarase deficiency Succinate dehydrogenase α-ketoglutarate dehydrogenase

Abnormalities / Diseases Associated With PDH And The TCA Cycle 3) Thiamine Deficiency -- classical beriberi, Pyuvate Dehydrogenase α-ketoglutarate Dehydrogenase

Regulation of the Tricarboxylic Acid Cycle? About half page to be submitted next Wednesday before The class. Students Review Question? Additional questions would be sent through the email on Thursday.

After Glycolysis What next after? Lactate (anaerobic) Glucose → 2 Pyruvate Acetyl-CoA (TCA cycle)

(Anaerobic conditions) 2. Conversion To Lactate (Anaerobic conditions) (oxidized) (reduced)

Cori cycle Lactate can be transported by blood Exercising muscles and the Cori Cycle Lactate can be transported by blood to liver and used in gluconeogenesis

How do cytosolic/cytoplasmic NADH get into the mitochondrial?

How do cytosolic/cytoplasmic NADH get into the mitochondrial? glycerol 3-phosphateshuttle - NADH as FADH malate-aspartate shuttle- NADH as NADH

The malate-aspartate shuttle.

Overview Of Carbohydrate Metabolism

Gluconeogenesis non-carbohydrate precursors are converted to glucose.

Gluconeogenesis Is Active Tissues In Which Gluconeogenesis Is Active liver Renal Cortex

Functions and importance Gluconeogenesis Maintaining the blood glucose in the fasted state But the brain, red blood cells, and renal medulla, rely on glycolysis for ATP.

Physiological Conditions In Which Gluconeogenesis Is Especially Active fasted state, when stored as glycogen is depleted plasma concentration of glucose decline

Physiological Conditions In Which Gluconeogenesis Is Especially Active During prolonged physical exercise. important in the neonate. (the first few hours after delivery).

Gluconeogenesis starting material lactate, pyruvate, Oxaloacetate glycerol Some amino acids propionic acid ( oxidation of odd-chain fatty acids and branched methyl fatty acids)

Biochemical Reactions Of Gluconeogenesis Most are the same as glycolysis, But in the opposite direction, With some few exceptions

Phosphofructokinase-1 Fructose 6-phosphate Glucose Glucose 6-phosphate Phosphohexose isomerase Hexokinase Phosphofructokinase-1 Fructose 1,6- bisphosphate Pyruvate kinase Phosphoenolpyruvate Pyruvate 2-Phosphoglycerate Phosphoglycerate mutase Glyceraldehyde 3-phosphate dehydrogenase 1,3-Bisphosphoglycerate Phosphoglycerate kinase 3-Phosphoglycerate

Three Physiologically Irreversible Steps Glycolysis And Gluconeogenesis Are Different Glucokinase/Hesosekinase ---glucose 6-phosphatase phosphofructokinase- 1 --fructose 1,6-bisphosphatase,

Three Physiologically Irreversible Steps Glycolysis And Gluconeogenesis Are Different 3. pyruvate kinase---------------- A) Pyruvate carboxylase B) Phosphoenolpyruvate carboxykinase

Localization of Gluconeogenesis Most Of The Enzymes Are Found In The Cytosol, But Pyruvate Carboxylase----- Mitochondria Glucose 6-phosphatase------ Lumen Of The Endoplasmic Reticulum

Regulation of gluconeogenesis

General Overview Of Metabolism (Carbohydrate, Protein, Fat)