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2.2: Catabolism of glucose-glycolysis as the first pathway tells us about some general metabolic principles

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    6045
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    10 First reaction of glycolysis.jpg

    11 glycolysis.jpg

    12 aldol condensationcleavage.jpg

    13 NAD.jpg

    14 G3Pdehydrog.mechanism.jpg

    15 Hydrolysis reactions.jpg

    Tables of standard free energies of hydrolysis

    Table A. Compounds considered to be "High Energy" Compounds

    Pi= inorganic phosphate (doesn’t specify a species) = major species at biological pH is \(\mathrm{HPO_{4}^{2-}}\)

    Compound

    (hydrolysis reaction is shown where more than one is possible)

    \(\mathrm{\Delta G^{\circ'}\: (kJ/mol)}\) Transfer Potential=\(\mathrm{|\Delta G ^{\circ'}|}\) Compound type

    Reason for large \(\mathrm{\Delta G^{\circ'}}\) of hydrolysis

    S=Substrate

    P=Product

    PEP -61.9 61.9 Enolic phosphate

    P tatuomerizes (pyruvate)

    P resonance stability (Pi)

    1,3-bisPGA -49.3 49.3 Acyl phosphate (phosphoric acid + carboxylic acid)

    P ionizaiton (PGA)

    Increased P resonance stability (Pi and PGA)

    Phosphocreatine -43.0 43.0 Guanidine phoshpate P resonance stability
    \(\mathrm{ATP \rightarrow AMP + PPi}\) -45.6 45.6 Phosphoric acid anhydride

    P resonance stability

    P ionization

    S bond strain due to electrostatic repulsion

    \(\mathrm{ADP \rightarrow AMP + Pi}\) -32.8 32.8 Phosphoric acid anhydirde Same as for \(\mathrm{ATP \rightarrow AMP + P}\)
    \(\mathrm{ATP \rightarrow ADP + Pi}\) -30.5 30.5 Phosphoric acid anhydride Same as for \(\mathrm{ATP \rightarrow AMP + P}\)
    UDP-Glucose -31.9 31.9 Sugar nucleotide

    P resonance stability

    P ionization

    Acetyl Coenzyme A -31.4 31.4 Thioester

    S no resonance stabilization

    P ionization

    P resonance stabilization

    S-adenosylmethionine -25.6 25.6 Sulfonium salt

    Sulfur more stable in P

    P less charge repulsion

    Table B. Compounds considered NOT to be "High Energy" Compounds

    Compound \(\mathrm{\Delta G ^{\circ'}\: (kJ/mol)}\) Transfer Potential Compound type Reason for \(\mathrm{\Delta G^{\circ'}}\) of hydrolysis smaller than compounds in Table A.
    \(\mathrm{AMP \rightarrow adenosine + Pi}\) -14.2 14.2 Phosphate ester

    S no destabilizing electrostatic repulsion

    P (Adenine) doesn't ionize

    \(\mathrm{Glc-6-P \rightarrow Glc + HPO_{4}^{2-}}\) -13.8 13.8 Phosphate ester S no electrostatic repulsion

    "high energy" bonds are those whose hydrolysis proceeds with \(\mathrm{\Delta G ^{\circ’}}\) more negative than -25kJ/mol

    Most values from Principles of Biochemistry pp. 521.

    17 Fermentation.jpg

    Systematic Common
    ATP:hexose 6-phosphotransferase Hexokinase
    ATP:GLC 6-phosphotransferase Glucokinase (liver)
    GLC-6-P ketolisomerase Phosphoglucose isomerase
    ATP:F-6-P 1-phosphotransferase Phosphofructokinase-1 (PFK-1)
    F-1,6-bisP G-3-P-lyase aldolase
    G-3-P ketolisomerase Triose phosphate isomerase
    G-3-P:(\mathrm{NAD^{+}}\) oxidoreductase (phosphorylating) G-3-P dehydrogenase
    ATP:3-PGA 1-phosphotransferase Phosphoglycerate kinase
    3-PGA 2,3-phosphoisomerase Phosphoglycerate mutase
    2-PGA hydro-lyase Enolase
    ATP:enol-pyruvate phosphotransferase Pyruvate kinase
    Lactate:\(\mathrm{NAD^{+}}\) oxidoreductase Lactate dehydrogenase
    Pyruvate carboxy-lyase Pyruvate decarboxylase
    Ethanol:\(\mathrm{NAD^{+}}\) oxidoreductase Alcohol dehydrogenase

    18 glycolysis as internal redox.jpg


    2.2: Catabolism of glucose-glycolysis as the first pathway tells us about some general metabolic principles is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts.

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