We reported previously on the purification and partial characterization of a putative microtubule-associated protein (MAP) from bovine adrenal cor-tex with an approximate molecular mass of 250 kDa. The protein was expressed ubiquitously in mammalian tissues, and bound to microtubules in vitro and in vivo, but failed to promote tubulin polymerization into microtubules. In the present study, partial amino acid sequencing revealed that the protein shares an identical primary structure with the widely distri-buted iron storage protein, ferritin
