College of Food Science and Engineering, Ocean University of China, No. 5, Yushan Road, Qingdao, Shandong Province 266003, China.
Food Funct. 2017 Dec 13;8(12):4441-4448. doi: 10.1039/c7fo01014a.
A calcium-chelating peptide is considered to have the ability to improve calcium absorption. In this study, Pacific cod skin gelatin hydrolysates treated with trypsin for 120 min exhibited higher calcium-chelating activity. Sequential chromatography, involving hydroxyapatite affinity chromatography and reversed phase high performance liquid chromatography, was used for the purification of calcium-chelating peptides. Two novel peptides with the typical characteristics of collagen were sequenced as GDKGESGEAGER and GEKGEGGHR based on LC-HRMS/MS, which showed a high affinity to calcium. Calcium-peptide complexation was further characterized by ESI-MS (MS and MS/MS) and FTIR spectroscopy. The results showed that the complexation of the two peptides with calcium was conducted mainly at the ratio of 1 : 1. The amino terminal group and the peptide bond of the peptide backbone as well as the amino group of the lysine side chain and the carboxylate of the glutamate side chain were the possible calcium binding sites for the two peptides. Meanwhile, several amino acid side chain groups, including the hydroxyl (Ser) and carboxylate (Asp) of GDKGESGEAGER and the imine (His) of GEKGEGGHR, were crucial in the complexation. The arginine residue in GEKGEGGHR also participated in the calcium coordination. Additionally, several active fragments with calcium-chelating activity were obtained using MS/MS spectra, including GDKGESGEAGE, GEAGER, GEK, EKG and KGE. This study suggests that gelatin-derived peptides have the potential to be used as a calcium-chelating ingredient to combat calcium deficiency.
一种钙螯合肽被认为具有提高钙吸收的能力。在这项研究中，用胰蛋白酶处理 120 分钟的太平洋鳕鱼皮明胶水解物表现出更高的钙螯合活性。连续色谱法，包括羟基磷灰石亲和色谱法和反相高效液相色谱法，用于钙螯合肽的纯化。两种新型肽基于 LC-HRMS/MS 被测序为 GDKGESGEAGER 和 GEKGEGGHR，具有胶原的典型特征，对钙表现出高亲和力。通过 ESI-MS（MS 和 MS/MS）和傅里叶变换红外光谱进一步表征钙-肽络合。结果表明，两种肽与钙的络合主要以 1:1 的比例进行。肽骨架的氨基末端基团和肽键以及赖氨酸侧链的氨基基团和谷氨酸侧链的羧基基团是两种肽的可能钙结合位点。同时，一些氨基酸侧链基团，包括 GDKGESGEAGER 的羟基（Ser）和羧基（Asp）以及 GEKGEGGHR 的亚氨基（His），在络合中至关重要。GEKGEGGHR 中的精氨酸残基也参与了钙配位。此外，使用 MS/MS 谱获得了具有钙螯合活性的几个活性片段，包括 GDKGESGEAGE、GEAGER、GEK、EKG 和 KGE。本研究表明，明胶衍生肽具有作为钙螯合成分用于防治钙缺乏的潜力。
