Multiformity of elongation factor eEF-2 isolated from rat liver cells.

Two fractions of eEF-2 (M(r) approx. 100,000 and M(r) approx. 65,000) were isolated from post-ribosomal supernatant of the rat liver cells. Only eEF-2, with mol. weight of about 100,000 Da, can be phosphorylated, but only eEF-2, with mol. weight of about 65,000 Da, was isolated from the active polyribosomes. The existence of two eEF-2 forms with different properties in the rat liver cells is striking and uncovers new aspects for the cellular function of this protein.