Abstract
As a first step in understanding the mechanism of vitellogenesis in the kuruma prawn Penaeus japonicus, biochemical characteristics of vitellin (Vt) were investigated. Vitellin was purified from vitellogenic ovary by gel filtration and ion-exchange chromatography, and an anti-Vt antiserum was raised in rabbits. The molecular weight of the purified Vt was estimated to be 530 kDa by native-polyacrylamide gel electrophoresis and gel filtration. Vitellin was composed of three polypeptide subunits of 91, 128, and 186 kDa in sodium dodecylsulfate-polyacrylamide gel electrophoresis. The 91 kDa subunit was further purified by reversed-phase high-performance liquid chromatography. A protein sequencer was used to analyze the amino-terminal amino acid sequence of the 91 kDa subunit; residues up to position 29 were identified, except for two residues at positions 10 and 14. Positive immunohistochemical reaction against the anti-Vt antiserum was observed in the cytoplasm of oocytes at endogenous and exogenous vitellogenesis stages.
