ligand binding and conformational change Flashcards
what is a proteome?
The entire set of proteins expressed within a genome
why is the proteome larger than the number of genes?
Due to alternative RNA splicing and post translational modification
what is a prosthetic group?
Non protein unit tightly bound to a protein necessary for its function
when does alternative splicing occur?
when a single gene can produce several different versions of a protein
what is a ligand?
A substance that can bind to a protein
What does ligand binding change?
the conformation of a protein causes a functional change in protein, induced fit
what happens when the active site has a high affinity for the substrate?
it orientates the substrate to lower the activation energy
what happens after the reaction when it has a low affinity?
moves away enzyme goes back to its normal shape
what is an allosteric enzyme?
has at least 2-4 binding sites
what is cooperativity?
changes in binding at one subunit alter the affinity of the remaining subunits
what structure is cooperativity?
proteins with quaternary structure
what do modulators regulate?
the activity of the enzyme when the y bind to the allosteric site
what does a positive modulator do?
Binds to the allosteric site on the enzyme
the active site has a conformational change so the substrate can now bind to the active site
what does a negative modulator do?
the modulator binds to the allosteric site on the enzyme
the active site has conformational change
The substrate can no longer bind to the active site
what happens to oxygen when the pH decreases or temperature increases
affinity of haemoglobin for oxygen lowers, binding of oxygen is reduced. Actively respiring tissue will reduce binding of oxygen to haemoglobin promoting increased oxygen delivery to tissue
