The peptide sequence RVPSL, derived from ovotransferrin in egg white, was also synthesized by the solid phase procedure using the Fmoc protected amino acid synthesis method (Shanghai Scientific Peptide Biological Technology Co., Shanghai, China).The synthesized peptide was purified by HPLC on an octadecyl silane column (Yu and others 2011). The purity and the molecular mass of the purified peptide were determined by HPLC and mass spectrometry (Dionex, MSQ, U.S.A.).