Abstract Pearls have high medicinal value. In the present study, we discovered the first bioactive peptide in pearls. The bioactive peptide, KKCHFWPFPW, was a novel angiotensin I-converting enzyme (ACE)-inhibitory peptide derived from the pearl matrix of Pinctada fucata . It was screened and identified using quadrupole time-of-flight mass spectrometry. The molecular weight of the peptide was 1417.5 Da, and its theoretical isoelectric point was 9.31. The half-maximal inhibitory concentration of the peptide was 4.17μM, as determined by high-performance liquid chromatography. The Lineweaver–Burk plot showed that this peptide competitively inhibited ACE activity. As the peptide concentration increased, the ACE inhibition rate also increased. The molecular docking was simulated using Maestro 2022-1 Glide software to understand the potential mechanisms underlying the ACE-inhibitory activity of KKCHFWPFPW. These results indicated that the peptide from the P. martensii pearl matrix might be a potential source of antihypertensive peptides.

Efficacy of the first bioactive peptide from the pearl