enzyme inhibitors

• What is a competitive inhibitor?

  have a similar shape to substrate

  they bind to the active site but no reaction takes place, instead the active site is blocked
• What is the effect of a competitive inhibitor?

  Without inhibitor line on top

  with competitive inhibitor line underneath
• What is a non-competitive inhibitor?

  Bind to a site other than the active site (allosteric site)

  causes the active site to change shape so that the substrate molecules can no longer fit
• What is the effect of a non-competitive inhibitor?

  Underneath competitive inhibitor line
• What is the difference between reversible and non-reversible inhibition?

  Reversible inhibition;

  weaker hydrogen bonds or weak ionic bonds. the inhibitor can be removed

  Non-reversible inhibition;

  Stronger covalent bonds, the inhibitor cannot be removed easily
• What is the normal enzyme reaction rate?

  Every active site is saturated

  the rate of reaction is at its highest
• Competitive inhibitor example- succinate dehydrogenase

  substrate is succinate which is converted to fumarate

  the substrate will soon find an active site, the effect of a competitive inhibitor is to slow down the process
• Non-competitive inhibitor example- copper sulphate and catalase

  the shape of the active site changes because the non-competitive inhibitor has bound to an allosteric site; so preventing an enzyme-substrate complex from forming= less products formed

  the reaction rate cannot reach the same point because the non-competitive inhibitors have changed the shape of some of the active sites