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. Concentration - Activity increases as concentration increases until it reaches a saturation point

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