When Y32 is expressed within a normal cell, what is true of its nucleotide binding site?
"The biosensor can bind both Mg2+-ATP and ADP with very high affinity (Km ∼ 1 μM). In the cytosol of a normal cell, the concentrations of ADP and Mg2+-ATP range in the hundreds of μM and approximately 1 mM, respectively."
A. It is most likely to be occupied by ADP.
B. It is unlikely to be occupied by Mg2+-ATP.
C. It is unlikely to be occupied by Mg2+-ATP or ADP.
D. It is effectively always occupied by Mg2+-ATP or ADP.