AS level. C.3 Enzyme inhibitors
How are enzymes activated?
How are enzymes inactivated?
What are the two types of enzyme inhibitors?
Competitive and non-competitive
Explain how competitive inhibitors inhibit an enzyme
A molecule which has the same or similar shape to the active site of the enzyme fits into the active site. This then blocks the substrate from entering the active site and prevents the reaction from happening.
Are competitive inhibitors temporary?
Yes, they only bind to the active site of an enzyme for a short amount of time.
What are the two examples of competitive inhibitors?
Statins and Aspirin
What are statins used for?
They decrease synthesis of cholesterol and so lower the blood cholesterol levels
What problems could high blood cholesterol levels cause?
What is aspirin used for?
Irriversible inhibits the active site of COX enzymes, preventing the synthesis of prostaglandins and thromboxane
What are the prostaglandins and thromboxane chemicals responsible for?
producing pain and fever
Explain how non-competitive inhibitors inhibit an enzymes
It binds to the allosteric site on the enzyme. This causes the tertiary structure of the enzyme to change and so the shape of the active site changes.
What enzyme can organophosphate inhibit?
What is organophosphate typically used for?
insecticides and herbicides
What is the enzyme acetyl cholinesterase necessary for?
Nerve impulse transmissions
What could happen if organophosphate inhibits the enzyme acetyl cholinesterase?
It could result in muscle cramps, paralysis and death (if ingested
What does PPIs stand for?
Proton pump inhibitors
What can be treated by PPIs?
How do PPIs treate long-term indigestion?
They erriversible inhibit an enzyme resposnible for secreting H+ ions into the stomach (stops the build up of excess acid)
What is meant by the term end-product inhibition?
It is where an enzyme inhibition occurs when the product of a reaction acts an inhibitor to the enzyme that produces it.
What is the result of end-product inhibition?
It means that their is negative-feedback control mechanism for the reaction
Does the process of end-product inhibition use competitive or non-competitive inhibition?
Non-competitive reversible inhibition
Glucose is broken down by adding two phosphate groups to the molecule. What is the name of the enzyme which catalyses the addition of the second phosphate group?
What does PFK stand for?
What is PFK conpetitively inhiited by?
How does ATP regulate its own production?
If a large amount of ATP is produced then more of it will bind to the PFK enzyme. This will prevent more ATP being produced.