Proteins of yeast ribosomal subunits: number and general properties.

1. Saccharomyces cerevisiae at the early stationary phase of growth accumulate 80 S ribosomes, easily dissociating into subunits, which retain full activity in phenylalanine polymerization in vitro. A simplified and efficient technique for large-scale preparation of yeast ribosomal subunits is proposed. 2. Presence of 34 proteins in 40 S subunit and 42 proteins in 60 S subunit was demonstrated by two-dimensional acrylamide-gel electrophoresis. Both ribosomal subunits contain acidic proteins: three in 60 S and six or seven in 40 S subunit. It seems that two of them correspond to prokaryotic proteins, L7 and L12. The total number of yeast ribosomal proteins is similar to those obtained for other Eukaryota.