Why is the T state of glycogen phosphorylase less active?
A) The adjacent amino acids are not phosphorylated; thus the catalysis cannot be carried out.
B) The active site is partially blocked.
C) ATP cannot be bound by the T state.
D) All of the above.
E) None of the above.

Question

Quizplus · Accepted Answer

The T state of glycogen phosphorylase has a partially blocked active site due to a movement of a loop that covers the catalytic site. This makes it less active than the R state, which has an open active site. The other options are not correct as the adjacent amino acids being phosphorylated is not necessary for catalysis and ATP can still bind to the T state.

Why Is the T State of Glycogen Phosphorylase Less Active