1. Enzyme Inhibition Examples

2. Inhibitors Molecules that reduce the rate of enzymatic reactions
Usually specific and work at low concentrations
Block the enzyme but they do not usually destroy it
Many drugs and poisons are inhibitors of enzymes in the nervous system.

3. Types of Enzyme Inhibition
Competitive Inhibition
Compete with the substrate molecules for the active site
The inhibitor’s action is proportional to its concentration
Resembles the substrate’s structure closely
Noncompetitive Inhibition
Not influenced by the concentration of the substrate
Inhibits by binding irreversibly to the enzyme but not at the active site
Cyanide

4. Types of Enzyme Inhibition
Competitive Inhibition
Non Competitive Inhibition

5. Penicillin Non Competative
Interferes with the synthesis of cell walls of reproducing bacteria
Inhibits an enzyme—transpeptidase
Defective walls cause bacterial cells to burst and die
Human cells are not affected because wehave cell membranes, not cell walls.
Some people (perhaps 5% of the population) are allergic to penicillin

6. Aspirin Non Competitive Inhibition
Inhibit the activity of the enzyme called cyclooxygenase (COX)
Suppress the production of prostaglandins
Cuts down on the pain signal to brain, swelling, and inflammation
Ibuprofen and naproxen work this same way

7. Methotrexate Competitive inhibition
Inhibits DNA synthesis in malignant tumor formation

8. CO
Competitive inhibitor to oxygen when it comes to binding to the heme group of hemoglobin

9. Cyanide Non competitive Causes death by halting ATP production
Binds to the allosteric site of the enzyme cytochrome oxidase
Changes the shape of the active site so that the enzyme cannot pass electrons on and stops ATP production

10. Sarin Gas
Competitive
Nerve agent; interferes with the normal signaling between nerve cells
Inhibiting the enzyme acetylcholinesterase
If this neurotransmitter is not removed, the muscles don't relax.
Binds at the active site on the cholinesterase molecule, making it unable to bind to acetylcholine.

11. Competitive vs. Non Completive Inhibition