title: Preparation of Antioxidant Peptides from Salmon Byproducts with Bacterial Extracellular Proteases.
abstract: Bacterial extracellular proteases from six strains of marine bacteria and seven strains of terrestrial bacteria were prepared through fermentation. Proteases were analyzed through substrate immersing zymography and used to hydrolyze the collagen and muscle proteins from a salmon skin byproduct, respectively. Collagen could be degraded much more easily than muscle protein, but it commonly showed weaker antioxidant capability. The hydrolysate of muscle proteins was prepared with crude enzymes fromPseudoalteromonassp. SQN1 displayed the strongest activity of antioxidant in DPPH and hydroxyl radical scavenging assays (74.06% ± 1.14% and 69.71% ± 1.97%), but did not perform well in Fe2+chelating assay. The antioxidant fractions were purified through ultrafiltration, cation exchange chromatography, and size exclusion chromatography gradually, and the final purified fraction U2-S2-I displayed strong activity of antioxidant in DPPH, hydroxyl radical scavenging assays (IC50= 0.263 ± 0.018 mg/mL and 0.512 ± 0.055 mg/mL), and oxygen radical absorption capability assay (1.960 ± 0.381 mmol·TE/g). The final purified fraction U2-S2-I possessed the capability to protect plasmid DNA against the damage of hydroxyl radical and its effect was similar to that of the original hydrolysis product. It indicated that U2-S2-I might be the major active fraction of the hydrolysate. This study proved that bacterial extracellular proteases could be utilized in hydrolysis of a salmon byproduct. Compared with collagen, muscle proteins was an ideal material used as an enzymatic substrate to prepare antioxidant peptides.
authors.affiliation: School of Life Science, State Key Laboratory of Medical Genetics, Central South University, Changsha 410013, China. ribang.wu@gmail.com.
authors.forename: Ribang
authors.initials: R
authors.lastname: Wu
authors.affiliation: Institute of Agro-Food Science and Technology & Shandong Provincial Key Laboratory of Agro-Products Processing Technology, Shandong Academy of Agricultural Sciences, Jinan 250100, China. chenleilei8210@163.com.
authors.forename: Leilei
authors.initials: L
authors.lastname: Chen
authors.affiliation: School of Life Science, State Key Laboratory of Medical Genetics, Central South University, Changsha 410013, China. liudan.forever@163.com.
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.affiliation: School of Life Science, State Key Laboratory of Medical Genetics, Central South University, Changsha 410013, China. 1608110217@csu.edu.cn.
authors.forename: Jiafeng
authors.initials: J
authors.lastname: Huang
authors.affiliation: School of Life Science, State Key Laboratory of Medical Genetics, Central South University, Changsha 410013, China. zhangjiang915@163.com.
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhang
authors.affiliation: School of Life Science, State Key Laboratory of Medical Genetics, Central South University, Changsha 410013, China. 162511013@csu.edu.cn.
authors.forename: Xiao
authors.initials: X
authors.lastname: Xiao
authors.affiliation: School of Life Science, State Key Laboratory of Medical Genetics, Central South University, Changsha 410013, China. leiming@csu.edu.cn.
authors.forename: Ming
authors.initials: M
authors.lastname: Lei
authors.affiliation: School of Life Science, State Key Laboratory of Medical Genetics, Central South University, Changsha 410013, China. lumc96@hotmail.com.
authors.forename: Yuelin
authors.initials: Y
authors.lastname: Chen
authors.affiliation: School of Life Science, State Key Laboratory of Medical Genetics, Central South University, Changsha 410013, China. helenhe@csu.edu.cn.
authors.forename: Hailun
authors.initials: H
authors.lastname: He
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D002850:Chromatography, Gel / Q000379:methods; D006868:Hydrolysis; D017665:Hydroxyl Radical / Q000737:chemistry; D010447:Peptide Hydrolases / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D011492:Protein Hydrolysates / Q000737:chemistry; D012474:Salmon / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D001426:Bacterial Proteins; D010455:Peptides; D011492:Protein Hydrolysates; D017665:Hydroxyl Radical; D010447:Peptide Hydrolases
keywords: antioxidant peptide; bacterial extracellular proteases; enzymatic hydrolysis; evaluation of antioxidant activity; peptide purification