Characterization and immunological analysis of ferritin from the hemolymphof Galleria mellonella

Ferritin, an iron-binding protein, was purified from the larval hemolymph o f the wax moth, Galleria mellonella by KBr density ultracentrifugation and FPLC (Superose 6). The iron content of ferritin was determined by atomic em ission spectroscopy and Ferene S stain. Native molecular mass of ferritin w as estimated as 630 kDa. SDS-PAGE revealed that the ferritin consists of tw o major polypeptides of 26 and 32 kDa and one minor polypeptide of 30 kDa. An isoelectric point of ferritin was measured to be approximately 7.3 and o nly the 32-kDa subunit is glycosylated. The ferritin contains large amounts of lysine, glutamine, glutamic acid and leucine but tryptophan was not det ected. Electron microscopic examination of negatively stained preparations showed an 11-nm particle in external diameter and 7-nm iron core. Ferritin is present in both the ovary and testis. Localization of ferritin by immuno electron microscopy in ovary and testis revealed that the gold particles we re located in vitelline membrane and yolk granules but not in follicular ep ithelium of ovary. In the testis, the gold particles were located in testic ular fluid and lumen of vas deferens. (C) 2001 Elsevier Science Inc. All ri ghts reserved.