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 ”

Examples SubstrateEnzyme Catalyzing MaltoseMaltase AmyloseAmylase LipidLipase PerioxidePerioxidase

 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:  Temperature  Concentrations of Enzyme and Substrate  Cell pH