Intermediary Metabolism

Intermediary MetabolismCHE132

Fructose metabolism

All the enzymes involve in fructose metabolism is found only in liver cell.

The G3P enters glycolysis.Lipids or Fats is digested by lipase to fatty acids

mitochondria

Fatty acid Transport and Activation

Beta Oxidation

Acetyl CoA enters the Krebs Cycle.

The fatty acid is repeatedly beta oxidize until all its carbon skeleton is converted to acetyl CoA.Sample problemHow many ATP (from NADH(2.5) and FADH2(1.5)) can be produced from palmitic acid (C15 COOH) the major fatty acid from pork?Seat work Stearic acid (C17COOH) is about 12-14% of Lard (the fat of Pork). How many ATP can be produced from 1 molecule of Stearic acid.Fate of Amino acid carbon skeleton

The carbon skeleton of amino acid are generally converted to different intermediate of Krebs cycle.Alanine transaminase, SGPT

Aspartate transaminase or SGOT or AST

AspartateAlpha ketoglutarateglutamateoxaloacetate

The Urea cycle occur in the liver and kidney cells

Umbrella Urea

Interesting facts about PROTEIN AND FAT metabolism1. High protein diets more likely damage the kidneys and liver.

2. Protein consume lots of ATP to remove NH3 thus Atkins diet results to weight loss.

3. L carnitine is part of the transport system of fatty acid into mitochondria.Quiz 11. The enzyme that converts glucose to glucose 6-phosphate is _________.2. The enzyme that regulates glycolysis is ______.3. What are the two phases of glycolysis?4. What enzyme convert a free fatty acid to acyl coA?5. What enzyme convert acyl coA and carnitine to acylcarnitine?Quiz 16. Malate dehydrogenase converts malate to _____?7. Glucose 6-phosphate is converted to glucose in what particular part of the cell?8. What enzyme converts an acyl coA to an enoyl coA?9. What enzyme converts a keto acyl coA to an acetyl coA and a new acyl coA?10. What vitamin is the precursor of coenzyme A(coA)?Electron Transport ChainOxidative phosphorylation is the process in which ATP is formed as a result of the transfer of electrons from NADH or FADH2 to O2 by a series of electron carriers.-Stryer

Electron Transport ChainOxidative phosphorylation generates 26 of the 30 molecules of ATP that are formed when glucose is completely oxidized to CO2 and H2O.-Stryer

Electron Transport ChainOxidative phosphorylation is conceptually simple and mechanistically complex.-StryerElectron transport chainThe unraveling of the mechanism of oxidative phosphorylation has been one of the most challenging problems of biochemistry.-StryerOxidative Phosphorylation in Eukaryotes Takes Place in MitochondriaEugene Kennedy and Albert Lehninger discovered a half-century ago that mitochondria contain the respiratory assembly, the enzymes of the citric acid cycle, and the enzymes of fatty acid oxidation

Mitochondria Are Bounded by a Double Membrane

Oxidative phosphorylation takes place in the inner mitochondrial membrane, in contrast with most of the reactions of the citric acid cycle and fatty acid oxidation, which take place in the matrix.Mitochondria Are the Result of an Endosymbiotic EventA free living organism capable of oxidative phosphorylation was engulfed by another cell.

The most mitochondrial-like bacterial genome is that of Rickettsia prowazekii, the cause of louse borne typhus.

High-Energy Electrons: Redox Potentials and Free-Energy Changes

A 1.14-Volt Potential Difference Between NADH and O2 Drives ElectronTransport Through the Chain and Favors the Formation of a Proton Gradient

Gibbs free energy of ATP rxn

D G = - 7.5 kcal mol-1 ( - 31.4 kJ mol-1) for the hydrolysis of ATP - StryerGlass electrode Nernst equationE = E - 0.0592pH32

Delta G of pumping H+=5.2 kcal/mol

The pH outside is 1.4 units lower than inside[corresponding to log10 (c 2/c 1) of 1.4]The membrane potential is 0.14 V, the outside being positiveElectrons Can Be Transferred Between Groups That Are Not in Contact

The Respiratory Chain Consists of Four Complexes: Three Proton Pumps and aPhysical Link to the Citric Acid Cycle

The High-Potential Electrons of NADH Enter the Respiratory Chain at NADH-QOxidoreductase

NADH-Q oxidoreductase is also known as NADH dehydrogenase and complex I.

The reduction of Q(ubiquinone)

Actually the electrons and H+ go to Flavins first

to iron sulfur cluster

before finally going to Q(ubiquinone).

Complex I

Ubiquinone,Q Is the Entry Point for Electrons from FADH2 of FlavoproteinsSuccinate-Q reductase complex (Complex II) is the same enzyme that converts succinate to fumarate and also transfers electrons from FADH2 to Q.Likewise the electrons are first transferred to iron sulfur complexBefore finally converting ubiquinone, Q to ubiquinol, QH2.Electrons Flow from Ubiquinol to Cytochrome c Through Q-Cytochrome cOxidoreductase

Q-cytochrome c oxidoreductase (also known asComplex III and cytochrome reductase)

Attachment of heme of cytochrome c

Transmembrane Proton Transport: The Q Cycle

Complex III

Cytochrome c Oxidase Catalyzes the Reduction of Molecular Oxygen to Water

Cytochrome c oxidase is also known as complex IV

Copper center B

Heme A

Complex IV

Quiz 31. Identify the enzyme that is responsible for transferring the electrons from NADH to ubiquinone.2. Identify the CYCLE THAT describe the transfer of electron from ubiquinol to cytochrome c.3. The other name for complex III is ____?4. Actually NADH transfers its electrons to _____ then to _____ before going to Q.5. This enzyme converts ADP to ATP.6. In ETC the final receiver of electron is ____ which is converted to water.Toxic Derivatives of Molecular Oxygen Such as Superoxide Radical AreScavenged by Protective Enzymes

Vitamin E and C are antioxidantsBecause it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation-StryerChemiosmotic Hypothesis: A Proton Gradient Powers the Synthesis of ATP

Peter Mitchell1978 Nobel Prize in Chemistry for his chemiosmotic hypothesis originally presented in 1961.

ATP Synthase Is Composed of a Proton-Conducting Unit and a Catalytic UnitATP synthase is also known as complex V

Proton Flow Through ATP Synthase Leads to the Release of Tightly BoundATP: The Binding-Change Mechanism

The World's Smallest Molecular Motor: Rotational Catalysis

Proton Flow Around the c Ring Powers ATP Synthesis

First Exam Topics1. Glycolysis2. Gluconeogenesis3. Krebs cycle4. Beta oxidation5. Electron transport system6. Urea cycle/Amino acid deamination

Electron transport system

Gluconeogenesis

Gluconeogenesis Is Not a Reversal of Glycolysis

The Conversion of Pyruvate into Phosphoenolpyruvate Begins with theFormation of Oxaloacetate

Pyruvate carboxylase

Carboxybiotin

Oxaloacetate leaves the mitochondria as malate

Malate is reconverted to oxaloacetate in the cytosolOxaloacetate Is Shuttled into the Cytosol and Converted intoPhosphoenolpyruvate

The Conversion of Fructose 1,6-bisphosphate into Fructose 6-phosphate andOrthophosphate Is an Irreversible Step

The Generation of Free Glucose Is an Important Control Pointglucose 6-phosphate is transported into the lumen of the endoplasmic reticulum.

where it is hydrolyzed to glucose by glucose 6-phosphatase.ATP and GTP

Six High Transfer Potential Phosphoryl Groups Are Spent in SynthesizingGlucose from Pyruvate

Glycogen link is alpha 1-4!!!

Glycogenesis

glycogenolysis

lipogenesis

lipogenesis