- At low substrate concentration, increasing the substrate concentration will result in a proportional increase in the rate of reaction.
- As there are sufficient active sites, the increase in substrate concentration will increase the frequency of effective collisions between the enzyme and substrate molecules, increasing the rate of formation of enzyme-substrate complex.
- However, at high substrate concentration, increasing the substrate concentration will no longer speed up the reaction.
- All the active sites of the enzyme molecules will be occupied at any given moment.
- Any added substrates have to ‘wait’ until existing enzyme-substrate complexes are dissociated and the active sites become available for binding.
- The rate of reaction can only be increased with the addition of enzymes.
 |
Enzyme concentration
- At low enzyme concentration, increasing the enzyme concentration will result in a proportional and linear increase in the rate of reaction.
- The increase in enzyme concentration provides more active sites which the substrate molecules can bind to, increasing the rate of effective collision and the formation of enzyme substrate complex.
- However, at high enzyme concentration, increasing the enzyme concentration will no longer have effect on the reaction as all the substrate molecules would already have been converted into their products.
- The rate of reaction can only be increased with the addition of substrates.
Image taken from: http://alevelnotes.com/content_images/i74_Image4.gif
Temperature
- Enzymes work best at their optimum temperature, which is usually 40°C.
- Below the optimum temperature, the rate of reaction increases linearly with the increase in temperature.
- As the temperature increases, kinetic energy of the molecules increase. This increases the rate of effective collisions between enzyme and substrate molecules and the formation of enzyme-substrate complex.
- Beyond the optimum temperature, the rate of reaction decreases even though the frequency of collisions increases.
- Thermal agitation of the enzymes break the hydrogen bonds, ionic bonds and hydrophobic interactions that stabilize the specific 3D conformation of the enzyme.
- The enzyme becomes denatured as the shape of the enzyme's active site is altered and is no longer complementary to that of the substrate.
Image taken from: http://alevelnotes.com/content_images/i71_gcsechem_18part2.gif
pH
- Enzymes work best at their optimum pH level.
- A change in pH level will result in the alteration of the ionic charge of the R groups of the amino acid residues.
- This breaks the ionic bonds and hydrogen bonds that are responsible for maintaining the specific 3D conformation of the enzyme.
- The enzyme becomes denatured as the shape of the enzyme's active site is altered and is no longer complementary to that of the substrate.
Image taken from: http://alevelnotes.com/content_images/i72_enzyme_ph_graph.gif
No comments:
Post a Comment