Flashcards in B2.045 Prework 2 Cooperativity and Allostery Deck (10)
what is the difference between allosteric and cooperative binding?
cooperative- same binding site, same ligand
allosteric- different binding site, different ligand
how is allostery seen on an enzyme curve?
shift in Kd
what are two types of allostery?
inhibitory allostery- initial substrate diminishes binding of second substrate
enhancing allostery- initial substrate enhances binding of second substrate
why does nature need allostery?
what are two examples of cooperativity?
homo-oligomers- binding site is repeated on each subunit
single polypeptide chain with identical binding sites
how can you visualize cooperativity on an enzyme curve?
steeper sigmoidal curve; midpoint is weighted average of a site with low affinity and a site with high affinity
what is the hallmark of negative cooperativity?
never reaches 100% bound
how is positive cooperativity used in nature?
response range to ligand change narrows, aka once a little binds, a lot more can bind
similar to an on/off
how is negative cooperativity used in nature?
changes at higher ligand concentrations do not affect protein function
constant protein function across a wide range of ligand concentrations