Aminoacyl transfer ribonucleic acid synthesis in toluene treated liver cells

Aminoacyl tRNA synthetases were studied in suspensions of individual liver cells made permeable to tRNA by treatment with toluene. Centrifugation of the toluene treated cells revealed that about 90% of the aminoacyl tRNA synthetase activity remained associated with the cell pellet. If the toluene treated cells were preincubated under assay conditions and then centrifuged, about 75% of the aminoacyl tRNA synthetase activity remained associated with the cell pellet suggesting that aminoacylation occurred within the cell. Aminoacyl tRNA synthesis in this system was dependent on exogenous tRNA, ATP, and Mg²⁺. Enzyme activity remained linear with time through about 10 min of incubation and a 10 fold increase in cell concentration. The product of the reaction was exclusively aminoacyl tRNA. This system should prove useful for study of macromolecular synthesis in mammalian cells.