Control of the rate of translational initiation can be exerted at the level of the activity of the guanosine triphosphate (GTP)-binding and hydrolyzing initiation factor, eIF-2. The efficiency with which eIF-2 recycles between the active GTP-bound form and the inactive GDPbound form is controlled by the action of the initiation factor depicted as Factor ? in Figure 3-1. What is the identity of this factor?

(A) eIF-1

(B) eIF-2B

(C) eIF-4A

(D) eIF-4E

(E) eIF-4G

  

 

Translation GDP GTP elF-2 Factor? GDP elF-2 GTP FIG. 3-1