Chemistry of Life

Biology chapter 2.4

Enzymes (Proteins)

Enzymes are proteins that act as catalysts in nearly all metabolic processes (essential for the functioning of any cell)

Catalysts are substances that speed up chemical reactions without being affected by the reaction themselves

Enzymes affect the synthesis of molecules and the release of energy

Enzymes are usually named for the particular chemical (substrate) whose reaction they catalyze; ending in the “ase”

ExamplesSubstrate Enzyme CatalyzingMaltose MaltaseAmylose AmylaseLipid LipasePerioxide Perioxidase

Enzymes have regions called active sites- slots on the enzyme molecule into which the substrate molecule fits during the reaction

Lock and Key

Where an enzyme molecule links with a substrate at the active site in a process known as an enzyme-substrate complex

The chemical fit between the active site and substrate must be exact

The substrate is chemically altered and products are formed

When the reaction is completed the enzyme molecule is unchanged and the products are separate

The enzyme is free to catalyze additional reactions of this substrate

Ready to repeat its catalytic action

of enzymes:

TemperatureConcentrations of Enzyme and Substrate

Cell pH