Effect of acid pH on macromolecular synthesis in L cells.

Eagle's medium adjusted to pH 6 was found to inhibit the rate of RNA and protein syntheses in monolayer cultures of L cells. Incubation of the cells at pH 6 decreased the rate of incorporation of amino acids into nascent peptide chains and caused a disaggregation of polyribosomes. Messenger RNA seemed to persist during the exposure of the cells to medium adjusted to pH 6, since protein synthesis resumed when the cells were transferred to recovery medium containing actinomycin D. The inhibitory effects of pH 6 on macromolecular synthesis were reversible and the viability of the cells exposed to pH 6 did not decrease. The permeability of the cells was not altered by the exposure to pH 6.