Purification and identification of an antioxidant peptide from Pinctada fucata muscle

Abstract

Pinctada fucata muscles were hydrolysed by alcalase and filtered using ultrafiltration membranes to obtain peptides with molecular weights (MWs) less than 5 kDa. The percolate was then freeze-dried and named crude antioxidant peptides mixture from Pinctada fucata muscles (AOP). In this study, AOP was purified sequentially using sephadex gel chromatography, next reversed-phase high-performance liquid chromatography. The MW of the antioxidant peptide from P. fucata muscle was 1039.56 Da. The amino acid sequence was Gly–Ala–Gly–Leu–Pro–Gly–Lys–Arg–Glu–Arg based on matrix-assisted laser desorption ionization mass spectrometry (MALDI-TOF). The natural peptide exhibits good scavenging capacity against free radicals; the IC50 of scavenging 2,2-diphenyl-1-picrylhydrazyl and ∙OH of FC2 were closer to vitamin C and butylated hydroxytoluence; however, the IC50 values of $$ \cdot {\rm{O}}_2^ - $$ of FC2 were a bit poor. Its antioxidant activity was attributed to the hydrophobic amino acid residues enriched in the N-terminal and electrophilic ability mediated by Glu and electron acceptors such as Lys and Arg. The synthesized peptide exhibited a reduced ability to scavenge free radicals compared to the natural peptide. The proposed method is a feasible technique to prepare antioxidant peptides from P. fucata and could be useful to obtain ingredients in nutraceutical and cosmetic applications.

Keywords

• Pinctada fucata muscle
• antioxidant peptide
• purification
• antioxidant activity
• structure