Unit 2 Section 3.3 Cofactors and Inhibitors
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- Created on: 25-04-14 19:05
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- Cofactors and Inhibitors
- Cofactors and Coenzymes
- Inorganic cofactors
- Some cofactors are inorganic molecules. They work by helping the enzyme and substrate to bind together
- They dont directly participate inn the reaction so aren't used up or changed in any way.
- EG.. Manganese ions are cofactors found in hydrolase
- They dont directly participate inn the reaction so aren't used up or changed in any way.
- Some cofactors are inorganic molecules. They work by helping the enzyme and substrate to bind together
- Organic Cofactors
- Some cofactors are organic molecules - these are called coenzymes.
- They participate in the reaction and are changed by it
- They often act as carriers, moving chemical groups between different enzymes. They're continually recycled during this process
- They participate in the reaction and are changed by it
- Some cofactors are organic molecules - these are called coenzymes.
- Inorganic cofactors
- Enzyme Inhibitors
- Enzyme activity can be prevented by enzyme inhibitors - molecules that bind to the enzyme that they inhibit. inhibition can be conpetitive or non-competetive
- Competetive Inhibitors
- Competetive Inhibitor molecules have a similar shape to that of the substrate molecules. They compete with the substrate molecules
- They compete with the substrate molecules to bind to the active site, but no reaction takes place
- Instead they block the active site, so no substrate molecules can fit in it
- How much the enzyme is inhibited depends on the relative concentrations of the inhibitor and substrate. if there's a high concentration of the inhibitor, it'll take up nearly all the active sites and hardly any of the substrate will get to the enzyme
- Instead they block the active site, so no substrate molecules can fit in it
- They compete with the substrate molecules to bind to the active site, but no reaction takes place
- Competetive Inhibitor molecules have a similar shape to that of the substrate molecules. They compete with the substrate molecules
- Non Competeive Inhibitors
- Non - competetive inhibitor molecules. bind to the enzyme away from its active site
- This causes the active site to change shape so the substrate molecules can no longer bind to it
- They Dont compete with the substrate molecules to bind to the active site because they are a different shape
- icreasing the concentration of the substrate wont make any difference 0 enyme activity will bestill be inhibited
- They Dont compete with the substrate molecules to bind to the active site because they are a different shape
- This causes the active site to change shape so the substrate molecules can no longer bind to it
- Non - competetive inhibitor molecules. bind to the enzyme away from its active site
- Reversible and Non Reversible Inhibition
- Inhibitors can be reversible or non reversible
- Which one they are depends on the strength of the bonds between the enzyme and the inhibitor
- if they're strong, covalent bonds, the inhibitor can't be removed easily and the inhibition is irreversible
- if they're wealker hydrogen bonds or weak ionic bonds the inhibitor can be removed and the inhibition is reversibe
- Metabolic Poisons
- metabolic poisons interfere with metabolic reactions causing damage illness or death
- they're often enzyme inhibitors in the exam you might be asked to desbribe the action of one named poison
- EG... Cynaide is a non competetive inhibitor of cytochrome c ozxidase, an enzyme that catalyses respiration reactions. cells that cant respire die
- they're often enzyme inhibitors in the exam you might be asked to desbribe the action of one named poison
- metabolic poisons interfere with metabolic reactions causing damage illness or death
- Drugs
- Some medical drugs are enzyme inhibitors
- for example. some antiviral drugs eg reverse transcriptase inhibitors are a class of antiviral developed to treat HIV, they work by inhibiting the enzyme reverse transcriptase, which catalyses the replication of viral DNA
- Some medical drugs are enzyme inhibitors
- Cofactors and Coenzymes
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