enzymes Flashcards
what occurs when a substrate binds to an enzyme?
Catalyze its conversion into a product molecule
what is negative feedback?
the END product of a reaction inhibits the reaction from continuing
A low Km means an enzyme binds to a substrate (less/more) easily?
more easily. (high binding affinity)
At a high Km the enzyme binds to the substrate (less/more) easily?
LESS easily. they don’t bind together very well (low binding affinity)
Do competitive inhibitors change Vmax?
No! It raises Km but has no impact on Vmax
Do non-competitive inhibitors change Vmax?
It decreases Vmax and has no effect on Km. This is because it doesn’t interfere with binding to the active site. The conformation of the enzyme has altered. Remember that non-competitive inhibitors bind to places other than the active site.
What is allosteric inhibition?
binds to the enzyme and induces the enzymes INACTIVE form
T/F: Allosteric inhibition prevents from binding to the active site but can be non-competitive or competitive.
TRUE
T/F: In Non-competitive inhibition, the substrate can bind but prevents the reaction from occuring.
TRUE
What is positive cooperativity?
one substrate attachment makes others attach more easily to other active sites
what is negative cooperativity?
after the first substrate attaches, the enzyme ALTERS to make additional attachments difficult
what is the Michaelis constant, Km?
the concentration of substrate at 1/2 Vmax.
if there is a low binding affinity between the enzyme and substrate, what would the Km be?
High Km!
What is cooperativity?
when an enzyme has multiple active sites that can regulate substrate binding
what is an example of positive cooperativity?
Hemoglobin. After it picks up one oxygen, it’s easier to pick up additional oxygen
