Kinetics of adsorption of colicin CA42-E2 and reversal of its bactericidal activity.

The kinetics of killing of Escherichia coli K-12 by colicin CA42-E2 have been studied, and the data were used to estimate the adsorption constant of this colicin under various environmental conditions. Evidence was obtained suggesting that the adsorption of colicin occurred in two stages; the earlier stage was reversible and did not lead to the death of the cell, the latter stage was irreversible and bactericidal. Cells which had adsorbed a lethal quantity of colicin could be rescued for a short time by inactivating the adsorbed colicin with trypsin. However, when the metabolic activity of the cells was totally arrested the lethal effect of adsorbed colicin was subject to trypsin reversal over long periods of time.