Possibility of the transformation of eEF-2 (100 kDa) to eEF-2 (65 kDa) in the peptide elongation process in vitro

Two active eEF-2 polypeptides of approximately 100 and 65 kDa were copurifi ed from rat liver cells and separated. The fate of eEF-2 (100 kDa) during i ts binding to ribosomes and in the translocation step of the peptide elonga tion process was investigated. It was shown that eEF-2 (100 kDa) did not ch ange its form during the process of binding to the ribosomes. In the postri bosomal supernatant, obtained from the postincubation mixture of the elonga tion process, only eEF-2 (65 kDa) was found. These results suggest that the form of eEF-2 (100 kDa), when bound to the ribosome duping the elongation process, is transformed to eEF-2 (65 kDa). (C) 1999 Academic Press.