title: A Specific Peptide with Calcium-Binding Capacity from Defatted Schizochytrium sp. Protein Hydrolysates and the Molecular Properties.
abstract: Marine microorganisms have been proposed as a new kind of protein source. Efforts are needed in order to transform the protein-rich biological wastes left after lipid extraction into value-added bio-products. Thus, the utilization of protein recovered from defattedSchizochytriumsp. by-products presents an opportunity. A specific peptide Tyr-Leu (YL) with calcium-binding capacity was purified from defattedSchizochytriumsp. protein hydrolysates through gel filtration chromatography and RP-HPLC. The calcium-binding activity of YL reached 126.34 ± 3.40 μg/mg. The calcium-binding mechanism was investigated through ultraviolet, fluorescence and infrared spectroscopy. The results showed that calcium ions could form dative bonds with carboxyl oxygen atoms and amino nitrogen atoms as well as the nitrogen and oxygen atoms of amide bonds. YL-Ca exhibited excellent thermal stability and solubility, which was beneficial for its absorption and transport in the basic intestinal tract of the human body. Moreover, the cellular uptake of calcium in Caco-2 cells showed that YL-Ca could enhance calcium uptake efficiency and protect calcium ions against precipitation caused by dietary inhibitors such as tannic acid, oxalate, phytate and metal ions. The findings indicate that the by-product ofSchizochytriumsp. is a promising source for making peptide-calcium bio-products as algae-based functional supplements for human beings.
authors.affiliation: The Key Laboratory of Analysis and Detection Technology for Food Safety of the MOE, College of Chemistry, Fuzhou University, Fuzhou 350108, China. caixx_0123@163.com.|Institute of Food and Marine Bio-Resources, College of Biological Science and Technology, Fuzhou University, Fuzhou 350108, China. caixx_0123@163.com.
authors.forename: Xixi
authors.initials: X
authors.lastname: Cai
authors.affiliation: The Key Laboratory of Analysis and Detection Technology for Food Safety of the MOE, College of Chemistry, Fuzhou University, Fuzhou 350108, China. ifmb2016@126.com.|Institute of Food and Marine Bio-Resources, College of Biological Science and Technology, Fuzhou University, Fuzhou 350108, China. ifmb2016@126.com.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Institute of Food and Marine Bio-Resources, College of Biological Science and Technology, Fuzhou University, Fuzhou 350108, China. kathleen369@163.com.
authors.forename: Jiaping
authors.initials: J
authors.lastname: Lin
authors.affiliation: The Key Laboratory of Analysis and Detection Technology for Food Safety of the MOE, College of Chemistry, Fuzhou University, Fuzhou 350108, China. nanyan_fu@fzu.edu.cn.
authors.forename: Nanyan
authors.initials: N
authors.lastname: Fu
authors.affiliation: Institute of Food and Marine Bio-Resources, College of Biological Science and Technology, Fuzhou University, Fuzhou 350108, China. shywang@fzu.edu.cn.
authors.forename: Shaoyun
authors.initials: S
authors.lastname: Wang
mesh_terms: D001682:Biological Availability; D018938:Caco-2 Cells; D002118:Calcium / Q000378:metabolism*; D019587:Dietary Supplements; D006801:Humans; D010455:Peptides / Q000302:isolation & purification* / Q000378:metabolism; D011492:Protein Hydrolysates / Q000737:chemistry*; D012995:Solubility; D058009:Stramenopiles / Q000378:metabolism*
chemical_list: D010455:Peptides; D011492:Protein Hydrolysates; D002118:Calcium
keywords: Schizochytrium sp.; calcium-binding peptide; cellular uptake; defatted protein hydrolysate; mechanism