title: Identification of novel peptides from 3 to 10kDa pine nut (Pinus koraiensis) meal protein, with an exploration of the relationship between their antioxidant activities and secondary structure.
abstract: In the present study, two novel peptides Lys-Trp-Phe-Cys-Thr (KWFCT) and Gln-Trp-Phe-Cys-Thr (QWFCT) were purified and identified from 3 to 10kDa pine nut (Pinus koraiensis) meal protein. Their cytotoxicity and antioxidant activities in vitro were determined. Additionally, pulsed electric field technology, antioxidant activities, and circular dichroism were used together to investigate the relationship between antioxidant activities and secondary structure. The results showed that neither peptide demonstrated cytotoxicity in HepG2 cells. KWFCT had higher values for 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition (67.43%±1.33%) and ferric-reducing antioxidant power (67.86±1.03mM Fe2+/mg), and Ac-QWFCT had higher values for 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) inhibition (74.9%±1.19%) and cellular antioxidant activity (916.32μmol of QE/100g) (P<0.05). The antioxidant activities reached their highest values when parameters of PEF were 5kV/cm and 2400Hz. An increase in antioxidant activities of Ac-QWFCT was correlated with a decrease in random coil content.
authors.affiliation: College of Food Science and Engineering, Jilin University, Changchun 130062, PR China.
authors.forename: Ruiwen
authors.initials: R
authors.lastname: Yang
authors.affiliation: College of Food Science and Engineering, Jilin University, Changchun 130062, PR China.
authors.forename: Xingfang
authors.initials: X
authors.lastname: Li
authors.affiliation: College of Food Science and Engineering, Jilin University, Changchun 130062, PR China; School of Food Science and Technology, Dalian Polytechnic University, Engineering Research Center of Seafood of Ministry of Education, Dalian 116034, PR China. Electronic address: linsongyi730@163.com.
authors.forename: Songyi
authors.initials: S
authors.lastname: Lin
authors.affiliation: National Laboratory of Enzymic Engineering, Jilin University, Changchun 130062, PR China.
authors.forename: Zuoming
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Food, Nutrition and Packaging Sciences, Clemson University, Clemson, SC 29634, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D002942:Circular Dichroism; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods*; D009754:Nuts / Q000737:chemistry*; D010084:Oxidation-Reduction; D028223:Pinus / Q000737:chemistry; D017433:Protein Structure, Secondary
chemical_list: D000975:Antioxidants
keywords: Activity-structure relationship; Antioxidant peptides; Circular dichroism (CD); Pine nut meal protein; Pulsed electric field (PEF); Random coil