Relationship between primary structure or spatial conformation and functional activity of antioxidant peptides from Pinctada fucata

Antioxidant peptides from Pinctada fucata are ubiquitous in nature and can be utilized as ingredients in cosmetics or functional foods to positively regulate oxidative species in the human body against oxidation. Here, mutated peptides and a homologous series of peptides were designed and prepared, based on the original peptide sequence of an antioxidant peptide from Pinctada fucata meat (PFMAP), to better understand the structural relationships, including primary structure, spatial conformation and activity. The results showed that the antioxidant activity factors in order of importance were spatial conformation, amino acid sequence, amino acid position, amino acid composition, peptide chain length and degree of side-chain amino acid glycosylation. Moreover, this protocol had incomparable advantages in purity, speed and cost of preparing polypeptides, relative to enzymatic hydrolysis or chemosynthesis methods. This study also supplies test data information and a theoretical basis for the higher-value application of polypeptides from marine sources.