Effects of puromycin aminonucleoside on protein synthesis in Absidia coerulea

Abstract

The incorporation of 14C-leucine, 14C-phenylalanine, and 14C-phenylalanyl-tRNA into protein was measured in ribosome preparations of the soil fungus Absidia coerulea. The incorporation depended on ribosomes and GTP, together with pH 5 fraction and an ATP-generating system, or cell sap. The addition of 5 × 10−5 M aminonucleoside to the fungal cultures in vivo decreased the subsequent incorporation in vitro except when the ribosomes were prepared with bentonite. The percentage dry weight and protein concentration in the 140 000 × g supernatant were decreased (15% and 30%, respectively) following addition of aminonucleoside in vivo. Preincubation of the cell-free system with 5 × 10−5 M or 5 × 10−4 M aminonucleoside caused a decrease in the. subsequent incorporation of 14C-leucine and 14C-phenylalanyl-tRNA into protein.