Characterization of mitochondrial ribosomes from yeast

A method for the preparation of mitochondrial ribosomes from yeast is presented. Mitochondrial ribosomes differ from their cytoplasmic counterpart in nucleotide composition, electrophoretic mobility of a number of their respective ribosomal proteins, and thermal denaturation profiles. The mitochondrial and cytoplasmic ribosomes have identical sedimentation coefficients (80 S) and dissociate into 60S and 40S subunits. These findings demonstrate that, in yeast, mitochondrial ribosomes are distinct from cytoplasmic ribosomes.