ACIDIC PROTEIN ASSOCIATED TO RIBOSOMES OF SACCHAROMYCES-CEREVISIAE - CHANGES DURING CELL-CYCLE

A large proportion of protein Ax, one of the three acidic proteins detected in S.cervisiae is found in the cell cytoplasm. The fraction of Ax associated with the ribosomes is partially released by treatment of these particles in conditions that remove the bound initiation factors but a residual amount remains tightly bound to the ribosomes. Protein Ax is associated with the large ribosomal subunit and the amount of protein in the particles duplicates as the celle enters the stationary phase. The amino acid composition of protein Ax is similar to those of other acidic proteins from the ribosomes of yeast and other species being very rich in alanine (21.3%), glycine (12.2%), aspartic acid (14.7%) and glumatic acid (14.3%). © 1979.