Mycobactin is a commercially available siderophore. Siderophores are chemicals synthesized by living organisms for the purpose of binding and/or transporting iron into cells. The chemical structure of Mycobactin J (the commercially available mycobactin used as a supplement in bacteriological media to support growth of MAP) was described by Schwartz and De Voss (Tetrahedron Letters 42:3653-3655, May, 2001).
MAP is considered incapable of synthesizing mycobactin and hence is dependent on the presence of mycobactin in culture media for growth. With minor exceptions, MAP is considered the only species of mycobacteria dependent on mycobactin for in vitro growth. Mycobactin-dependency is a characteristic used to distinguish MAP from other mycobacteria that may be isolated during the culture assay of manure or tissue samples.