Abstract: Egg yolk phosvitin is the highest phosphorylated protein found in the nature,and is considered to be the best source for phosphopeptides production. Phosphopeptides can effectively bind calcium,iron and magnesium,and inhibit the formation of insoluble calcium phosphates or iron complexes.Phosphopeptides are developed as a new carrier to promote the body′s absorption of calcium,iron and magnesium.In this paper,several important technologic conditions of phosvitin preparation,including buffer solution,pH and dilution times were optimized by the single factor test and orthogonal experiment.The results showed that phosvitin can be well isolated with 10 volumes of 0.05 M pH 5.2 NaAc buffer dilution.The yield of phosvitin was 90 mg from 10 mL of egg yolk,and its the phosphorus content was 7.2%,the N/P ratio was 3.9.Furthermore,the phosvitin product was dephosphoried with 0.2 M NaOH for 2 h,and then hydrolyzed with trypsin for 4 h to get phosphopeptide.In the further experiment,the phosvitin phosphopeptide product was demonstrated to have a strong activity of blocking formation of calcium phosphate precipitation,and its calcium binding ability reached up to 9.1%.Altogether,these results laid solid foundation for further in vivo studying the function of phosvitin phosphopeptide.

Key words: phosvitin, phosvitin phosphopeptide, calcium binding