A poly(U)-binding factor stimulating EF-1 activity in the wheat germ soluble fraction

A poly(U)-binding activity is present in the high-speed supernatant fraction of embryo homogenates from wheat seeds. The factor responsible for such activity was found to have a stimulatory effect on the elongation factor 1 (EF-1). It copurifies with EF-1L, the lighter form of EF-1, through Sephadex G-200, DEAE-cellulose, hydroxyapatite and poly(U)-Sepharose 4B column chromatography. The two factors could be separated only through a heating step which destroyed EF-1 activity whilst leaving most of the poly(U)-binding activity unaltered.