mass spectrometry.
The HPLC result
showed that the purity of the peptide RVPSL was 98.60%, and
the mass spectrum of the peptide confirmed its MW and sequence
(Figure 2). The peptide RVPSL showed a high activity
with an IC50 value at 20 μM (Figure 3). The ACE-inhibitory
activity of RVPSL was comparable to or higher than that of small
peptides such as Glu–Gly–Gly–Tyr–Arg, Val–Lys–Ala–Gly–Phe,
Leu–Val–Gln–Gly–Ser, and so on (Saiga and others 2003; Guan
and others 2009; Muguruma and others 2009; Rho and others
2009). Miguel (Miguel and others 2004) reported that RADHPL
(IC50 6.2 μM) and YAEERYPIL (IC50 4.7 μM) from egg white
had high ACE-inhibitory activity. Ovokinin (Fujita and others
1995) from egg ovalbumin has been documented to be able to
significantly inhibit the ACE, with peptide sequence FRADHPFL
corresponding to the residues 358 to 365 of ovalbumin.
Based on that research, it was hypothesized that peptides from
egg with a certain degree of ACE-inhibitory activity might be
related to the “Leu” located in C terminal of peptides.