STUDIES ON THE RECEPTOR SITE OF ESCHERICHIA COLI FOR COBALTOUS ION

抄録

Studies were made in locating the receptor site of Eseheriehia coli K-12 for cobaltous ion, and the following results were obtained:
(1) The amount of cobalt ion which can be fixed by E. coli, cultured both in a broth and a synthetic minimum medium, was greatly suppressed when the cells were treated wtih copper or nickel ions simultaneously and even when they-were added with radioactive cobalt ion after washing and removing these heavy mtals. These results would indicate that
(2) The cobalt-receptor is a common receptor for nickel and copper, and, furthermore, the fixation of copper or nickel ion to this receptor was much stabler than that of cobalt ion, and
(3) That cobalt ion, bound with the cellular receptor, is easily exchange-able by molecules of cobalt ion by each other.
(4) When the cells cultured in a broth medium were starved, its fixing ability was relatively decreased. This result suggests that the reverse amino acids can play some part as a cobalt receptor site of E. coli.