Hydrolysis of Glucose-6-Phosphate Glucose 6-phosphatase ∆Gº = –3.3 kcal/mol = –13.8 kJ/mol

High ∆Gº Hydrolysis Compounds High energy ~ ∆Gº = –14.8 kcal/mol = –61.9 kJ/mol

High ∆Gº Hydrolysis Compounds Another one ∆Gº = –11.8 kcal/mol = –49.3 kJ/mol

High ∆Gº Hydrolysis Compounds Another form of high energy. ∆Gº = –10.3 kcal/mol = –43 kJ/mol

Phosphate Anhydrides (Pyrophosphates) ATP ∆Gº = –7.3 kcal/mol = –30.5 kJ/mol

Thiol Esters ∆Gº = –7.5 kcal/mol = –31.4 kJ/mol Thiol ester - high energy ∆Gº = –7.5 kcal/mol = –31.4 kJ/mol

Thiol Esters Thiol ester less resonance-stabilized Thiol ester are high energy Thiol ester less resonance-stabilized

“High-Energy” Compounds Large ∆Gº hydrolysis Bond strain (electrostatic repulsion) in reactant ATP Products stabilized by ionization Acyl-P Products stabilized by isomerization PEP Products stabilized by resonance Creatine-P Contributors

“High-Energy” Compounds “High-energy” compound is one with a ∆Gº below –6 kcal/mol (–25 kJ/mol) Definition

High-Energy Compounds Table of high-energy compounds

Group Transfer Potential The intermediate step.

Adenylates

ATP

ADP

AMP

Glycerol 3-phosphate - a hydroxy ester; low energy

Resonance forms

A pyrophosphate

High-energy phosphates

Free energies of hydrolysis of several phosphates

Source of energy in an organism versus time of use.

ATP supplies energy for the pink and is made by the blue reactions.

Most reduced structure has most energy. Oxidation harvests the energy.

Fatty acid has lots of calories; glucose has less - already more oxidized.

A regular compound energetically

Chemiosmotic separation of protons provides the energy for oxidative phosphorylation.

Catabolism of polymer to simple unit of acetyl~CoA then complete oxidation and oxidative phosphorylation.

Energy charge = [ATP] + 0.5 [ADP]/[ATP] + [ADP] + [AMP] How much is “charged” in the ATP form.

ATP

Chemical Sense in Metabolism Lecture 25 Chemical Sense in Metabolism Chemical sense is important. Biochemicals follow the laws of chemistry.