Protein synthesis in rabbit reticulocytes. Demonstration of the requirements for eIF-2 and Co-eIF-2A for peptide chain initiation using immune sera.

Antisera to eIF-2 and Co-eIF-2A have been prepared by immunizing two chickens separately with homogeneous preparations of either eIF-2 or Co-eIF-2A. Addition of anti-eIF-2 or anti-Co-eIF-2A to reticulocyte lysates strongly inhibits protein synthesis and, in each case, protein synthesis inhibition is reversed by the addition of the corresponding homogeneous factor. Protein synthesis inhibition by anti-Co-eIF-2A is not reversed by eIF-2 at any concentration tested indicating an absolute requirement for Co-eIF-2A in protein synthesis. Also, in partial peptide chain initiation reactions, the addition of anti-Co-eIF-2A inhibits Co-eIF-2A stimulation of ternary complex formation by eIF-2 and Co-eIF-2A protection of ternary complexes in the presence of aurintricarboxylic acid.