RELATIONSHIP BETWEEN VITELLOGENIN AND ITS RELATED EGG-YOLK PROTEINS IN SAKHALIN TAIMEN (HUCHO-PERRYI)

Vitellogenin (Vg) and its three egg yolk protein products, lipovitelli n (Lv), phosvitin (Pv) and beta'-component, were isolated from mature female Sakhalin taimen (Hucho perryi). Vg had an apparent molecular we ight of 540 kDa and appeared as a major 240 kDa Land in SDS-PAGE, whic h resolved into two major Lands (165 and 125 kDa) after reduction. The estimated molecular weights oi purified Lv, Pv, and beta'-component w ere 330, 23, and 30 kDa, respectively. Lv appeared as a main band oi 1 50 kDa in SDS-PAGE which resolved into two smaller bands (92 and 29 kD a) after reduction. beta'-component appeared as a 34 kDa band before a nd as a 17 kDa band after reduction. Except for Pv, the purified prote ins all reacted with an antiserum to Vg. In SDS-PAGE, Pv appeared as a 23 kDa band and a second < 6.5 kDa diffuse Land. An antiserum to Pv d ephosphorylated by alkaline phosphatase (Ap) was prepared. In Western blots, the antiserum reacted with dephosphorylated Pv and Vg, but not with Lv and beta'-component. This is the first immunological proof cha t three egg yolk proteins (Lv, Pv, and beta'-component) are derived fr om Vg in fish.