definitions of enzyme classifications

Oxidation-reduction (Redox) reactions

Any chemical reaction in which the oxidation numbers (oxidation states) of the atoms are changed

Transfer of functional groups

the transfer of a functional group (e.g., a methyl or phosphate group) from one molecule (called the donor) to another (called the acceptor)

Hydrolysis

a chemical compound decomposes by a reaction with water. The hydrolysis reaction breaks down a variety of polymers, including proteins, carbohydrates, fats, and nucleic acids

Lyases

catalyzes the breaking of various chemical bonds by means other than hydrolysis and oxidation, often forming a new double bond

Isomerization

structural rearrangement of isomers (same molecular weight but different structural formulas).

Ligases

reaction joining of two large molecules by forming a new chemical bond

Holoenzyme

A catalytically active enzyme with its cofactor complex

Apoenzyme

enzyme without the cofactor

the transition state in a chemical reaction

The point of highest free energy. a species whose reacting bonds are midway to being formed or broken, as the case may be.

Free Energy of Activation (ΔGǂ)

difference in free energy between reactants and transition state. ΔG ‡ = ΔG - ΔG RXN

From a thermodynamic perspective, the rate of a reaction (k) is proportional to

e^(-ΔG‡/RT)

ΔΔG‡cat

ΔΔGcat‡ = ΔGuncat‡–ΔGcat‡

is the difference in ΔG‡ values for catalyzed and uncatalyzed reactions.

Indicates efficiency of catalyst.

mathematical rate enhancement of an enzyme

e^(ΔΔG‡cat/RT)

what do enzymes do in terms of thermodynamics and kinetics?

Enzymes do not affect reaction equilibria. They Lower the activation energy (ΔG ‡ ).

Arrhenius Equation

k = Ae^(-ΔG‡cat/RT)

A describes a constant for a particular reaction, not to be confused with the reactant species A.

Indicates the relationship between activation energy and the rate constant for the reaction.