Over 90% of the yolk zinc has been reported to be bound to lipovitellin which was also shown to bind copper We found that turkey egg phosvitin contains a significant amount of bound copper and zinc In fact, it has been suggested that phosvitin might function as an antioxidant by binding iron (Fe2+) and copper (Cu2+) present in yolk, thereby inhibiting a metalcatalyzed oxidation of yolk phospholipids