inhibitors

• enzyme activity can prevented by enzyme inhibitors, which are molecules that bind the enzyme that they inhibit
• enzyme inhibiton can be competitive or non-competitive
• competitive inhibitor molecules have a similar shape to that of the substrate molecules
• competitive inhibitors compete with the substrate molecules to bind to the active site but no reaction takes place. instead they block the active site so no substrate molecules can fit in it
• the relative concentrations of inhibitor and substrate affect by how much the enzyme is inhibited
• a high concentration of competitive inhibitor will take up nearly all of the enzyme's active sites and hardly any of the substrate will get to the enzyme
• if there is a higher concentration of substrate than competitive inhibitor, then the chances of the substrate getting to the active site before the inhibitor increases. increasing the concentration of the substrate will increase the rate of reaction (up to a point - until all the active sites are filled)
• non-competitive inhibitor molecules bind to the enzyme away from the active site
• non-competitive inhibitor molecules cause the active site to change shape so the substrate molecule cannot bind with it.
• increasing the concentration of a substrate won't make any difference to the reaction rate if non-competitive inhibitor molecules are present because enzyme active activity will still be inhibited