Promotion of Citrate Transport of the Transport-negative Mutants of Aerobacter cloacae

The “citrate transport-enhancing factor” obtained from Aerobacter cloacae did stimulate uptake of radioactive citrate by Escherichia coli, having an intrinsic barrier against citrate permeation. In order to prove function of the factor in the cells of Aerobacter, citrate transport-negative mutants of A. cloacae were isolated. These mutants were found to be lacking in the factor. Addition of the factor to these mutants resulted in stimulation of uptake of citrate. These results evidenced that the factor played an essential role in the citrate transport system of A. cloacae.