Enzymes Flashcards
What is the active site formed from?
Different parts of the primary sequence - doesn’t have to be adjacent
Why are active sites in clefts?
To exclude H2O molecules
What type of bond is there between enzymes and substrates?
Give an example
Why?
Weak bonds - they are not covalent
H
Allows the products to be released
What does the Vmax mean?
Reaction rate when the enzyme is fully saturated by substrate
(The maximum rate)
What does Km mean?
Concentration of the substrate at which half of the active sites of the enzyme are occupied by the substrate
(Conc of enzymes at half Vmax)
What is 1 unit?
The amount of enzyme to produce 1umol of product per min under standard conditions
What is the rate of an enzyme catalysed reaction proportional to?
Concentration of enzymes
How would a competitive inhibitor effect the graph?
Km increases and Vmax unaffected
Adding enough substrate will overcome the effect of the inhibitor
How would a non-competitive inhibitor effect the graph?
Km unaffected and Vmax decreases
Lowers conc of effective enzymes
How is the kM related to affinity?
Lower the kM
Higher the affinity of an enzyme to the substrate
What affects the Vmax?
The enzyme conc - positively
What does a high level of creatine kinase suggest?
Muscle damage - cardiac or cellular
What is an irreversible inhibitor?
A substance that permanently blocks the action of an enzyme
On the special graph what axis is the Vmax and Km?
Which inhibitor affects them?
Vmax - y non-competitive
Km - x competitive
