You Have Duplicated the Threonine to Isoleucine Metabolic Pathway and Want

Multiple Choice

You have duplicated the threonine to isoleucine metabolic pathway and want to determine the saturation level of threonine.You slowly add increasing amounts of threonine and observe that the reaction rate initially increases slowly and then decreases.You also note that increasing the amount of isoleucine decreases the rate of the reaction.You determine that the pathway is thus regulated by

A) feedback inhibition.
B) a noncompetitive inhibitor.
C) a competitive inhibitor.
D) a coenzyme.
E) a prosthetic.