Specificity of exochelins for iron transport in three species of mycobacteria.

Iron chelated to the water-soluble extracellular iron-binding compound (exochelin) from Mycobacterium smegmatis was taken up by that organism by an energy-coupled transport system which was not found in M. bovis BCG or M. intracellulare. The uptake of iron from the chloroform-soluble exochelins produced by the latter two species was by an inhibitor-insenstive system which was also found in M. smegmatis.