[Effect of hexammine cobaltchloride on the transport of bivalent cations in liver mitochondria]

It is found that hexammine cobaltichloride (HAC) which interacts with anionic groups of sulphate-containing glycosamine glycanes, is a specific inhibitor of mitochondrial transport of Ca2+ (semi-maximal inhibition in the presence of 6 nmoles HAC/mg of protein) and Sr2+ (semi-maximal inhibition in the presence of 30 nmoles HAC/mg of protein). Mn2+ translocation was inhibited by considerably higher HAC concentrations, 4-fold increase in the transport rate being observed in the presence of 15 nmoles/mg of protein. Inhibition of Ca2+ translocation is competitive, and its inhibition constant is 6-10(-6) M. HAC (3-120 muM) does not affect respiration, oxidative phosphorylation and DNP-stimulated ATPase activity of liver mitochondria, but at the concentration of 15 muM it decreases markedly the activity of "detergent" ATPase from liver mitochondria. It is suggested that the effect of HAC is due to its interaction with anionic groups of mitochondrial glycoproteins.