ENZYMOLOGY PT. 1

• Apoenzyme is the protein part of the enzyme without the cofactor necessary for catalysis
• Activator is an affecter molecule that increases the catalytic activity of an enzyme when it binds to a specific site
• Inhibitor is a substance that diminishes the rate of a chemical reaction
• Catalytic activity is the property of a catalyst that is measured by the catalyzed rate of conversion of a specified chemical reaction procured in a specified assay system
• Coenzyme combines with apoenzymes to form compounds called holoenzyme
• Enzyme is a protein that catalyzes chemical reactions without being destroyed, altered, and consumed.
• Properties of enzyme

  1. Specific for substrate
  2. Normally confined within cells unless allowed to roam bloodstream
  3. Appear in serum after cellular injury and degradation of cell
• Isoenzymes are a group of related enzymes catalyzing the same reaction but are different in structure, and physical, biochemical, and immunological properties.
• International unit is the unit used in quantifying amount of enzyme needed in converting one micromole of substrate per minute.
• Substrate is the reactant in a catalyzed reaction
• Product is the substance produced by the enzyme-catalyzed conversion of a substrate
• Active site is the specific portion of enzyme that binds on the substrate
• An active site is a water free cavity
• Allosteric site is the other cavity which may bind regulatory molecules
• An allosteric site can either bind an activator molecule or an inhibitor molecule
• In the Emil Fisher's Lock and Key theory of enzymes, enzymes have rigid active sites that means one kind of substrate can only fit an enzyme
• In Kochland's Induced Fit Theory it states that an enzyme has a flexible active site and changes based on the substrate that is to bind to it.
• Enzymes catalyze the chemical reaction by lowering the activation energy of the reaction.
• Activation energy is the minimum energy needed to start a reaction and convert the substrate into products.
• Transition state is the molecular intermidiate between substrate and its product thru which the reaction passes.
• The movement of energy in chemical reactions is downward or downhill. High energy reactants going to the lower energy of the product.
• Absolute specificity is when an enzyme combines only with one substrate and catalyzes only one reaction.
• Group specificity is when an enzyme can bind to all substrate within a chemical group
• Bond specificity is when an enzyme will only bind to a substrate that has a specific chemical bond present within its structure.
• Stereoisomers are enzymes that bonds with substrates that have the same formula but differ in the orientation of molecules
• Michaelis Menten Kinetics states that the rate of enzyme-catalyzed reaction is proportional to the concentration of the substrate.
• According to the Michaelis Menten Kinetics, If the reaction has reached its maximum velocity there will no longer be any further reaction to occur.
• Formula for Michaelis Menten Kinetics

  $v=$\frac{V_\text{max }[{S}]}{K_{{M}}+[{S}]}
• The value of Km represents the substrate concentration required for half of the maximal velocity (Vmax) of an enzymatic reaction.
• The value of Vmax represents the maximum possible rate at which an enzyme catalyzes a reaction under given conditions.
• The Zero Order Reaction is when the rate of a reaction is independent of the concentration of the reactants. It Depends on the concentration of the Enzymes present to react.
• First-order reaction is where the rate of reaction is directly proportional to the substrate concentration. This means the more substrate, the faster the reaction.
• Second-Order Reactions are reactions that depend on two reacting species. The rate of this type of reaction depends on both concentrations of the reactant molecules. The reaction quadruples in rate
• Oxidoreductases are enzymes that catalyze the transfer of electrons from one molecule to another. Typically from an oxidant to a reductant.
• Oxidoreductases usually requires cofactors such as NADPH, FAD, or NADP
• Hydroxylases add hydroxyl groups to a substrate.
• Oxidases are enzymes where the oxygen molecule is the hydrogen or electron acceptor.
• Peroxidases are enzymes that catalyzes reduction of hydrogen peroxide and organic hydroperoxides
• Reductase enzymes catalyzes reduction reactions
• Oxygenases are enzymes that catalyzes incorporation of intramolecular oxygen into organic substrates