Enzyme

how do enzymes work

• made of protein mainly

• act as biological catalysts which hold active sites which is a region where the substrate/reactant binds to for the process of enzyme catalysis

included fit model

• the substrate will attach to enzyme by H-bonding then break off into 2 monosaccharides

what is inhibition

• its the control of an enzyme based on a molecule called an inhibitor

The types of inhibitor

Competitive Inhibition: The inhibitor looks like the substrate and competes for the active site, blocking the reaction.

Non-Competitive Inhibition: The inhibitor binds to a different spot on the enzyme and changes its shape so the substrate can’t bind.

Allosteric Regulation: A molecule binds to a different spot on the enzyme and can either turn it on (activator) or off (inhibitor) by changing its shape.

Feedback Inhibition: The final product of a reaction stops an earlier step to prevent too much product from being made.

Factors affecting

Temperature:

• Increasing temperature generally increases enzyme activity because particles move faster

  and collide more often.

• If the temperature gets too high, the enzyme can change shape (denature) and stop

  working.

• If it’s too cold, reactions slow down.

- Enzyme concentration:

• More enzyme = faster reaction, as long as there is enough substrate to work on.

• If the substrate runs out, the rate levels off even if enzyme amount keeps increasing.

- Substrate concentration:

• More substrate = faster reaction until all enzyme active sites are “busy.”

• Once enzymes are saturated, the rate plateaus and won’t go faster.

  - pH:

• Each enzyme has an optimal pH (best pH for its shape/function).

• Too high or too low pH can denature the enzyme or change its active site, slowing or

  stopping the reaction.

Extra

• The enzyme has an active site that is specific to a particular substrate.

• The substrate will be attracted to the active site by h-bonds, and electrostatic attractions. The substrate binds into the active site to form the enzyme substrate complex.

• Any time something attaches to the enzyme it causes a change in the enzyme's 2°, 3°, 4° structures by altering the H-bonds and electrostatic attractions between amino acids within the protein. This change in shape by the enzyme causes the reaction to occur.

• Once the reaction occurs the products are released and the enzyme returns to normal ready to start all over again.