Enzymes and Activation Energy — Quick Reference

Activation Energy

• Activation energy is the energy required for a reaction to proceed. Represented as E_a.
• Enzymes are catalysts that speed up reactions by lowering the activation energy: Ea^{\text{lowered}} < Ea.

Enzymes and the Enzyme-Substrate Complex

• Enzymes are proteins with a 3D shape.
• Substrate binds to the active site to form the enzyme-substrate (ES) complex: \text{E} + \text{S} \rightarrow \text{ES} \rightarrow \text{E} + \text{P}.
• Substrate is the reactant; product is the substance produced by the reaction.
• Enzyme is unchanged after the reaction; more enzymes → faster reaction (rate proportional to enzyme concentration).

Active Site

• Active site is the region on the enzyme where the substrate fits and the reaction occurs.

Denaturation, Cofactors, and Enzyme Function

• Denaturation destroys the enzyme's ability to function.
• Cofactor is a non-protein component required by some enzymes.

Temperature Effects on Enzymes

• Warmer → enzyme works faster.
• Too hot → enzyme denatures.
• Too cold → enzyme still works but very slowly.

pH Effects on Enzymes

• Low pH can destroy the protein or affect its shape.
• pH is the measure of hydrogen-ion concentration.

DNA Polymerase and Nucleotides

• DNA polymerase is an enzyme.
• Substrates (nucleotides) include bases such as guanine, cytosine, thymine, phosphate, and deoxyribose sugar.
• Suffix "-ase" denotes an enzyme.

Quick Reference

• Substrate, product, ES complex, active site, and denaturation basics.
• Enzyme concentration increases reaction rate.