A dimeric complex of ruthenium: a new inhibitor of respiration-driven calcium transport in Escherichia coli K12.

Succinate-driven calcium uptake by everted membrane vesicles from Escherichia coli was sensitive to 2 mM-KCN and a dimeric, mixed valence complex of ruthenium, Ru2 (NH3)6Br5(H2O) (100 micro M), but relatively insensitive to 100 micro M-Ruthenium Red. The sensitivity of uptake to KCN and the slight inhibition caused by Ruthenium Red could be attributed to the different potencies of these compounds as respiratory inhibitors. Respiration was completely insensitive to the dimeric ruthenium complex, however, suggesting that this compound is an inhibitor of respiration-driven calcium transport.