A biologist has isolated an enzyme from human liver cells growing in culture. She observes that the enzyme's catalytic activity increases with increasing concentrations of adenosine diphosphate (ADP), even though ADP is not a substrate of the enzyme. The biologist hypothesizes that ADP may be acting as a noncovalent allosteric effector. Which experiment would be the best choice for testing her hypothesis? A. Make an ADP analogue that reacts covalently with an amino acid R group, test its ability to increase catalytic activity of the enzyme, and analyze the location of the amino acid it reacts with.
B. Run catalytic reactions in the presence of ADP and observe whether ADP undergoes chemical change.
C. Block the catalytic site with an irreversible inhibitor and test whether ADP can release the enzyme from this state of inhibition.
D. Denature the enzyme and then add 14C-labeled ADP, followed by measuring the amount of carbon-14 label that becomes covalently bound to the enzyme.
E. Both c and d