Characterization of Tissue‐Ferritin Purified from Wax Moth, Galleria mellonella

Abstract

ABSTRACT Tissue‐ferritin was homogeneously purified from the hemolymph‐free whole body of Galleria mellonella larvae. Tissue‐ferritin was composed of four subunits, 26, 30, 32 and 34 kDa. The 34 kDa subunit among them was specifically found in tissue ferritin while its N‐terminal sequence of 19 amino acid residues was identical to that of 32 kDa hemolymph‐ferritin subunit. It was observed that the 32 and 34 kDa subunit of tissue‐ferritin were glycosylated like 32 kDa subunit of hemolymph‐ferritin. It suggests that the 34 kDa subunit is an isoform of 32kDa ferritin subunit according post‐transcriptional modification. By semi quantitative RT‐PCR, the distribution of 32 kDa ferritin subunit mRNA was observed in fat body, Malpighian tubules, integument, and muscle, but found in a very small amount in silk gland or not found in gut. On the other hand, 26 kDa subunit mRNA was found in all organs tested although it was in a small quantity found in gut and silk gland. By dietary Hg treatment, 34 kDa subunit of tissue‐ferritin was clearly up‐regulated.