Binding analysis of ferritin with heme using α-casein and biotinylated-hemin: detection of heme-binding capacity of Dpr derived from heme synthesis-deficient Streptococcus mutans.

Bacterial and mammalian ferritins are known to bind heme. The use of α-casein and biotinylated hemin could be applicable to detection of protein-bound heme and of proteins with heme-binding capacity, respectively. Although commercial horse spleen ferritin and purified horse spleen ferritin (L:H subunit ratio=4) bound to an α-casein-coated plate, and this binding could be inhibited by hemin, recombinant iron-binding protein (rDpr), derived from heme-deficient Streptococcus mutans and expressed in Escherichia coli, did not bind to an α-casein-coated plate.