SDS-PAGE analysis of eIF4F, eIFiso4F, and mixed complexes. SDS-PAGE was carried out on a 12.5% acrylamide gel and stained with Coomassie Brilliant Blue. Each lane contains 25 pmol of the indicated complex. First lane, native eIF4F; second lane, recombinant eIF4F; third lane, eIF4G-eIFiso4E; fourth lane, eIFiso4G-eIF4E; fifth lane, recombinant eIFiso4F; sixth lane, native eIFiso4F.