B2.007 LG Flashcards
how do you determine the rate of reaction?
slope of concentration vs time
what is the purpose of an enzyme inhibitor?
the ligand binds and diminished catalysis to prevent a rxn from occuring
what characterizes a reversible inhibitor?
ligand readily dissociates
what characterizes an irreversible inhibitor?
ligand does not dissociate before the protein degrades or the patient dies; may be a covalent bond
what are the 3 types of reversible inhibitors?
competitive, non-competitive, uncompetitive
what is Km?
the [S] at half of vmax
what is on the y axis of a lineweaver-burke plot?
1/v0
what is on the x-axis of a lineweaver burke plot?
1/[S]
what do the x and y intercepts of the lineweaver-burke plot represent?
x axis: Km
y-axis: vmax
how do competitive inhibitors work?
compete with substrate for same form/site of the enzyme
which step is affected by competitive inhibition?
binding step only
how does a competitive inhibitor affect an enzyme activity curve?
Km increases
Vmax stays the same
what does a larger Km indicate?
less effective enzyme, takes a higher substrate concentration to get the same result as an enzyme with a lower Km
how to non-competitive inhibitors work?
inhibitor can bind to either just the enzyme, or the ES complex and inactivate it
what would be functionally similar to having a non-competitive inhibitor present?
having less enzyme
how does non-competitive inhibition affect an enzyme activity curve?
Km stays the same vmax decreases (like having less enzyme)
how does uncompetitive inhibition affect an enzyme activity curve?
changes Km and vmax
how do aspirin and ibuprofen inhibit COX differently?
ibuprofen is reversible and is secreted within 24 hrs
aspirin is irreversible and persists until entirely new platelets are made 7-10 days later
which type of reversible inhibition does irreversible inhibition mimic on the enzymatic activity curve?
non-competitive; less overall enzyme function
