{ Enzyme Inhibition Why enzymes don’t work

 An enzyme is just a folded protein Remember!!!

 Organic catalysts-speed up the rate of the reaction  Proteins  have –ase after their name Enzymes are…

Enzymes

 Enzymes fit together with substrates to aid a chemical reaction  Lock and Key vs Induced Fit  Video on my website that you need to watch and take notes Due by Friday! Enzymes

 There are several things that can effect the rate at which an enzyme works: temperature, pH, enzyme concentration, substrate concentration, and the presence of inhibitors or activators. Things effecting the rate at which and enzyme works

 When and enzyme stops working in its normal manner. This could be due to a variety of inhibitors including: nonspecific, competitive, and noncompetitive. What is enzyme inhibition?

 Non-specific: Any physical or chemical change that ultimately denatures any enzyme – irreversible  Denature – when the enzyme loses its folded shape; it basically falls apart because bonds have been broken Non-specific vs Specific

 Temperature – normally if you increase a temperature you speed up a reaction. However if you increase the temperature too much and it is no longer in the enzymes optimum range it will cause it to denature. Things that can cause an enzyme to denature

Example of a protein that has denatured due to increased temperature

 pH – an increase or decrease of pH out of the enzymes optimum range can cause denaturation. Things that can cause an enzyme to denature

 Specific inhibition – only works on specific enzymes, not all of them  Competitive and non- competitive inhibition Non-specific vs specific

Competitive vs non-competitive

 An inhibitor competes with the substrate for the active site  Like a race  Normally reversible if other substrates are available for the inhibitor to bind with Competitive Inhibition

 An inhibitor binds to the enzyme at a site different than the active site.  This special site that is just for the inhibitor is called the allosteric site Non-competitive Inhibition

 The binding of the inhibitor to the allosteric site normally changes the conformation of the active site so the substrate and enzyme can’t bind Non-competitive Inhibition

 Normally this type of inhibition is not permanent.  However this is not true in all cases, sometimes it is irreversible and the enzyme can no longer work. Non-competitive Inhibition

 Cofactors are non-protein inorganic chemical compounds bound to a protein  Helps the protein function during biochemical reactions and increase the rate at which the enzyme works  Coenzymes are organic molecules (usually vitamin or mineral) that are required by certain enzymes to carry out reactions Cofactors and Coenzymes