I. Characteristics of Enzymes A. Catatytic Proteins 1. Change rate of reactions 2. Never used or consumed B. Lower the Ea C. Do not affect free energy D. Act on specific substrates E. Affected by environment 1. Temperature 2. pH 3. Cofactors 4. Inhibitors a. competitive inhibition b. noncompetitive inhibition II. Progress of A Reaction - The Energy Profile A. Reactants absorb energy to break bonds B. Meet the Ea and reactants become unstable C. Bonds break and reform as energy is released III. Substrate Specificity and Induced-Fit A. Molecular specificity for a substrate B. Importance of 3D Conformation C. The Active Site D. Induced Fit to activate the enzyme E. Principle of saturation F. SE Complex IV. Regulation of Enzymes A. Regulation by gene transcription B. Regulation by altering activity once enzyme is made 1. Allosteric regulation a. Must be made of 2 or more polypeptide subunits b. The allosteric site vs. the active site 1. allosteric activators 2. allosteric inhibitors 2. Feedback Inhibition 3. Cooperativity 4. Subcellular Localization