T. Matsubara et al., CHANGE OF LIPOVITELLIN DURING IN-VITRO OOCYTE MATURATION IN JAPANESE FLOUNDER PARALICHTHYS-OLIVACEUS, Fisheries science, 61(3), 1995, pp. 478-481
The change in molecular weight in the native form of lipovitellin duri
ng in vitro oocyte maturation was examined by gel chromatography in Ja
panese flounder, Paralichthys olivaceus, a marine teleost which lays p
elagic eggs. The major protein peak at 400 kDa in the gel chromatogram
of post-vitellogenic oocyte homogenate disappeared, and a new 140 kDa
peak was observed in ovulated eggs. Both 400 kDa and 140 kDa yolk pro
teins were immuno-reactable to the specific antiserum against female s
pecific-serum protein, suggesting that the 400 kDa yolk protein was li
povitellin of this species and the 140 kDa one was a proteolytic deriv
ative from the 400 kDa lipovitellin. The time course analysis of the p
roteolysis of the lipovitellin during in vitro maturation demonstrated
that the lipovitellin of 400 kDa was cleaved into 140 kDa during the
later half of oocyte maturation. In combination with the result of SDS
-PAGE analysis, this seems to be caused by the proteolytic cut-off of
the 108 kDa peptide which constructs 400 kDa lipovitellin.