Selective inhibition of mitochondrial synthesis in Saccharomyces cerevisiae by canavanine

Canavanine, a structural analogue of arginine, selectively affects protein synthesis in yeast mitochondria in vivo in certain strains. This is also true for p-fluorophenylalanine, an analogue of phenylalanine, although there is no correlation in activity between these two analogues. These effects on mitochondria are detectable as (1) inhibition of growth of cells on non-fermentable medium, (2) considerable decrease in the amounts synthesized of the mitochondrial enzymes cytochromes a and b and (3) greatly reduced respiratory activity. Differences up to 100-fold are seen in the effects of the analogues on the cytoplasmic and mitochondrial systems, respectively. Spontaneous mutations to resistance that affect one or other system, but not both, have been isolated. In two cases of mitochondrial resistance to canavanine, the controlling genetic factors were nuclear.