{Enzyme Inhibition

Why enzymes don’t work

An enzyme is just a folded protein

Remember!!!

Organic catalysts-speed up the rate of the reaction

Proteins have –ase after their name

Enzymes are…

Enzymes

Enzymes fit together with substrates to aid a chemical reaction

Lock and Key vs Induced Fit Video on my website that you

need to watch and take notesDue by Friday!

Enzymes

There are several things that can effect the rate at which an enzyme works: temperature, pH, enzyme concentration, substrate concentration, and the presence of inhibitors or activators.

Things effecting the rate at which and enzyme works

When and enzyme stops working in its normal manner. This could be due to a variety of inhibitors including: nonspecific, competitive, and noncompetitive.

What is enzyme inhibition?

Non-specific: Any physical or chemical change that ultimately denatures any enzyme – irreversible

Denature – when the enzyme loses its folded shape; it basically falls apart because bonds have been broken

Non-specific vs Specific

It fell apart

Temperature – normally if you increase a temperature you speed up a reaction. However if you increase the temperature too much and it is no longer in the enzymes optimum range it will cause it to denature.

Things that can cause an enzyme to denature

Example of a protein that has denatured due to increased temperature

pH – an increase or decrease of pH out of the enzymes optimum range can cause denaturation.

Things that can cause an enzyme to denature

Specific inhibition – only works on specific enzymes, not all of them

Competitive and non-competitive inhibition

Non-specific vs specific

Competitive vs non-competitive

An inhibitor competes with the substrate for the active site

Like a race Normally reversible if other substrates are available for the inhibitor to bind with

Competitive Inhibition

An inhibitor binds to the enzyme at a site different than the active site.

This special site that is just for the inhibitor is called the allosteric site

Non-competitive Inhibition

The binding of the inhibitor to the allosteric site normally changes the conformation of the active site so the substrate and enzyme can’t bind

Non-competitive Inhibition

Normally this type of inhibition is not permanent.

However this is not true in all cases, sometimes it is irreversible and the enzyme can no longer work.

Non-competitive Inhibition

Cofactors are non-protein inorganic chemical compounds bound to a protein Helps the protein function during

biochemical reactions and increase the rate at which the enzyme works

Coenzymes are organic molecules (usually vitamin or mineral) that are required by certain enzymes to carry out reactions

Cofactors and Coenzymes