cooperativity

• which protein structure shows cooperativity?

  quaternary structure
• cooperativity

  the binding of a ligand at one subunit causes a conformational change. this then alters the conformation in the neighbouring subunits which increases the ligands affinity of the remaining subunits.
• cooperativity between substrate and active site

  the binding of a substrate to the active site of one subunit causes conformational changes in other subunits so their active site become active.
• cooperativity of haemoglobin and oxygen

  changes in the binding of oxygen at one subunit alter the affinity of the remaining subunits for oxygen.
• two factors that can influence the binding of oxygen are?

  Increased temperature and decreased pH lower the affinity of haemoglobin for oxygen so the binding of oxygen is reduced and vice versa.
• why are reversible conformational changes important?

  the addition or removal of a phosphate causes reversible conformational changes and is an important method of regulating activity of many proteins like enzymes or receptor molecules. Acts as a molecular switch.
• What enzyme catalyses phosyphorylation?


  kinases
• what is the action of a kinase?

  kinases transfer a phosphate from ATP to other proteins, activating.
• what changes in charge occur as a result of phosphorylation?


  adding a phosphate adds negative charges to the molecule. Ionic interactions in the unphosphorylated protein can be disrupted and new ones created.
• what enzyme catalyses dephosphorylation?


  phosphatases
• what is the action of a phosphatase?

  phosphatases rapidly remove phosphate groups from proteins, inactivating them. removes negative charges from the molecule.