Regulating Proteins Flashcards
What is an isoenzyme?
Different forms of the same enzyme(They catalyse the same reaction but have different kinetic properties)
What is product inhibition?
Accumulation of the product inhibits the forward reaction.
What is allosteric regulation?
Sigmoid relationship between rate and sub start e conc. Eg haemoglobin and oxygen- one bonded oxygen increases the affinity.
What is an alllosteric effector?
Something that binds to the enzyme away from the active sister which changes the state of the enzyme from its T state to its R state by giving conformational change.
What is an example of allosteric regulation
AMP and fructose-2 and 6-bisphosphate activate phosphofructokinase
ATP and H+ and citrate inhibit it.
This is a key regulator in glycolysis.
What’s the most common covalent modification to enzymes to help regulation?
Phosphorylation
Which enzyme phosphorylated and what enzyme reverses this.
Protein kinases transfer a phosphate from ATP to the -OH on SER, THR and TYR
Protein phosphates reverse this by hydrolysis removal of a phosphoryl group
What is a zynogen?
Digestive enzymes.
What stimulates the intrinsic pathway?
Damaged endothelial lining of blood cells stimulates binding of factor 12.
In blood clotting what stimulates the external pathway?
Trauma releases tissue factor
What is a peptidase?
Something that cuts up peptide bonds
How do we stop clotting so al the circulating blood doesn’t clot?
Localisation of thrombin, get more dilute and are removed by the liver.
Digestion by Proteases eg Protein C is activated my thrombin when at a certain level and they breaks down some clotting factors.
