Factors affecting enzymes

• Temprature

  -if temperature is too low there is not enough kinetic energy for successful collisions between the enzyme and substrate

  -if the temperature is too high enzymes denature , the active site changes shape and the enzyme substrate complex cannot form. this is because the ionic and hydrogen bonds holding the amino acids in their fixed tertiary structure in the active site are broken, especially the weak hydrogen bonds.
• PH

  -too high (many OH- ions) or too low (many H+ ions) of a pH will interfere with the charges in the amino acids in the active site. This can break bonds (mainly ionic and hydrogen) holding the tertiary structure in place and therefore the active site changes shape.

  -therefore the enzyme denatures and fewer enzyme-substrate complexes form.

  -small changes in pH do not cause a permanent changes to the enzyme because bonds can easily be reformed.

  -different enzymes have a different optimal pH.
• substrate and enzyme concentration

  if there is insufficient substrate, then the reaction will be slower as there will be fewer collisions between the enzyme and substrate.

  if there is insufficient enzymes then the enzyme active sites will become saturated with substrate and unable to work any faster