Vitellogenin is the major yolk protein of eggs where it is used as a food source during embryogenesis. Synthesized in the fat body and ovarian follicle cells and accumulate in the oocyte. Expressed in females only. By beta-ecdysone; in males. Tyrosine sulfation occurs in the female only and plays an essential functional role. Belongs to the AB hydrolase superfamily. Lipase family.