Enzymes

What Are Enzymes? Most enzymes are Proteins with specific shapes Act as Catalyst to accelerates a reaction Not permanently changed in the process

Enzymes Are specific for what they will catalyze Are reusable End in –ase -Protease -Lactase -Catalase

How do Enzymes Work? Enzymes work by lowering activation energy

Enzymes Without Enzyme With Enzyme Free Energy Progress of the reaction Reactants Products Free energy of activation

Enzyme-Substrate Complex The substance (reactant) an enzyme acts on is the substrate Enzyme Joins Substrate

Active Site A restricted region of an enzyme molecule which binds to the substrate. Enzyme Substrate Active Site

Affecting Enzyme Activity Three factors: 1. Environmental Conditions 2. Cofactors and Coenzymes 3. Enzyme Inhibitors

1. Environmental Conditions 1. Temperature - High temps may denature (unfold) the enzyme. - Low temps do not affect enzyme 2. pH (most like 6 - 8 pH near neutral) - Outside optimal range enzyme denatures 3. Ionic concentration (salt ions)

2. Cofactors and Coenzymes Inorganic substances (minerals like zinc and iron) and organic substances (vitamins) are sometimes need for proper enzymatic activity. Example: Iron must be present in the quaternary structure - hemoglobin in order for it to pick up oxygen.

Enzyme Inhibitors a. Competitive inhibitors: resemble an enzyme’s normal substrate and compete with it for the active site Enzyme Substrate Competitive inhibitor

Enzyme Inhibitors b. Noncompetitive inhibitors: do not bind at active site, but bind to another part of the enzyme causing a change in shape Enzyme Noncompetitive Inhibitor Substrate active site altered