Purification and characterization of liver ferritins from different animalspecies

The ferritins were purified from liver homogenates of buffalo, camel, cattl e, sheep and shark by thermal denaturation, ammonium sulphate fractionation , Sephacryl S-300 gel filtration and DEAE-blue gel affinity chromatography. The yield and iron content of affinity-purified liver ferritins ranged fro m 0.008 to 0.052 mg/g and 3.17% to 11.4% respectively. As they are glycopro teins, the ferritins contained variable amounts of neutral carbohydrates. E xcept for shark ferritin, the ferritins all exhibited immunological cross-r eactivity with anti-buffalo liver ferritin and anti-horse spleen ferritin b y immunodiffusion and immunoelectrophoresis. Gel electrophoresis, gel filtr ation and ultracentrifugal analysis indicated the presence of a monomeric f erritin in all cases. SDS-gel electrophoresis of shark ferritin gave a prot ein band of 18 kDa. Ovine, buffalo and bovine ferritin comprised two protei n subunits, the H (20 and 21 kDa) and the L types (18 and 19 kDa). Oligomer ic ferritin subunits with molecular weights of 27, 37 and 55 kDa were also found for bovine and buffalo ferritin. SDS-PAGE of camel ferritin revealed a complex pattern with four prominent bands of 61, 51, 44 and 39 kDa. Two f ast-migrating components of 15 and 16 kDa were also found in the purified l iver ferritins, including reference preparations. The PO43-/Fe ratios of pu rified shark (0.10) and bovine ferritin (0.12) were similar to that of stan dard equine spleen ferritin (0.11). However, the ratio was higher in ovine (0.17), camel (0.22) and bovine (0.26) ferritins. The amino acid compositio ns, molecular weights and sedimentation coefficients of the different liver ferritins were similar.