Endergonic and exergonic reactions reflect changes in Gibbs free energy (δG). Enzymes lower activation energy to speed up reaction.

Proteins as enzymes/catalysts, structures, antibodies/immune responses, motors and machines. Movie on protein motors.

Effect of activation energy on reaction rate, and function of catalysts.

Characteristics of catalysts - specificity, function, binding pocket for substrates, and transition states. Example showing transfer of phosphate from ATP to glucose.

Discussion of the structure and function of macromolecules, with a particular focus on enzymes/catalysts.

Energetics of reactants and products, and activation energy. Enzymes as biological catalysts and transition state complex. Nomenclature used in enzymatic reactions involving S (substrate/reactant), E (enzyme), ES (transition state), and P (product).

Enzyme-substrate interaction due to physical (shape) and chemical (amino acid properties) complementarity between the active site and the substrate. Three ways activation energy can be lowered: Proximity/orientation, induced-fit, and donation of charges to substrates. Example: Sucrase, phenylalanine hydroxylase.

Multiple ways to regulate enzymes. pH regulation through side chain protonation; temperature regulation through protein structure; covalent modification through phosphorylation; cofactors and coenzymes.

Function and mechanism of enzyme activators and inhibitors. Positive and negative feedback loops in a metabolic pathway. Definition: Reversible, irreversible, competitive, non-competitive, allosteric regulation. Example: Cancer drug Gleevec (competitive kinase inhibitor).

Chemical reactions are based on thermodynamics and kinetics. Free energy diagram shows the energy of reaction, and the effect of enzymes on the activation energy.

Definition of enzyme, catalyst, substrate, and active site. Free energy diagram and enzyme mechanism. Michaelis-Menten enzyme kinetics, Km and Vmax.

Chemical interactions between an enzyme and a substrate in its binding pocket.

Solution (PDF)^#

Enzymes, catalytic pockets, and reaction energetics. Contains a figure of all amino acid side chains as well as single letter and triple letter abbreviations.

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Free energy, energy storage, spontaneous reactions, and the use of biological catalysts.

Solution (PDF)

Enzyme kinetics including calculation of rates, Vmax, and Km.

Solution (PDF)

Label parts of a basic free energy diagram and how enzymes change the diagram.

Solution (PDF)