Purification and characterization of lipovitellin from Pacific saury Cololabis saira

ABSTRACT:   Lipovitellin (Lv), the major yolk protein derived from vitellogenin (Vg), was purified from vitellogenic ovaries of Pacific saury Cololabis saira using hydroxylapatite column chromatography followed by gel filtration. The apparent native mass of purified Lv was approximately 420 kDa, while the tertiary structure of Lv revealed by sodium dodecylsulfate–polyacrylamide gel electrophoresis was typical of teleost Lvs, consisting of a heavy chain (∼99 kDa) and a light chain (∼34 kDa). Western blot analysis using rabbit antiserum raised against Pacific saury Lv revealed a specific reaction with a polypeptide (∼194 kDa) that is present in serum from female Pacific saury but not in male serum, suggesting the approximately 194-kDa polypeptide to be the Vg monomer. This study describes the first step toward the development of specific immunoassays for Pacific saury Vg, which will be an effective tool for monitoring the reproductive development of this species.