STUDY OF PHOSPHORYLATION OF TRANSLATION ELONGATION FACTOR-II (EF-2) FROM WHEAT-GERM

Phosphorylation of elongation factor 2 (EF-2) by specific Ca2+/calmodu lin-dependent kinase is considered as a possible mechanism of regulati on of protein biosynthesis in animal cells at the level of polypeptide chain elongation. In this report we show that wheat germ EF-2 can be intensively phosphorylated by the rabbit reticulocyte EF-2 kinase. Pho sphorylation results in inhibition of the activity of plant EF-2 in po ly(U)-dependent cell-free translation system. Thus, the activity of EF -2 in plant cells can be potentially regulated by phosphorylation. How ever, we could not detect endogenous EF-2 kinase activity in wheat ger m either in vitro or in vivo. Furthermore, EF-2 kinase activity is not displayed in different organs of wheat and other higher plants.