Purification and Identification of Lipid-Lowering Protein from Barley Extract after <i>Lactiplantibacillus plantarum</i> dy-1 fermentation
Jiayan Zhang, Mengting Liu, Huan Deng, Yansheng Zhao, Ying Zhu, Juan Bai, Xiang Xiao
Abstract
Previous studies have found that the protein in barley extract fermented by Lactiplantibacillus plantarum dy-1 has the ability to inhibit lipid accumulation. However, the isolation, purification, and structural identification of the protein with lipid-lowering activity were still needed. In the present study, barley protein fermented by L. plantarum dy-1 with the optimal lipid-lowering ability was isolated and purified in three steps: using ammonium sulfate precipitation, anion-exchange chromatography, and size-exclusion chromatography. Combined with the model of HepG2 cells induced by oleic acid, the results showed that the pure protein LFBEP-C1 had the best lipid-lowering potential. Furthermore, our research found that LFBEP-C1 enriched the content of hydrophobic amino acids in LFBEP-C1. Ultraviolet spectroscopy analysis indicated that the glycosidic bond in LFBEP-C1 was an O-type glycosidic bond. The FTIR and circular dichroism spectra indicated that α-helix and random coil were the main secondary structures of LFBEP-C1. Mass spectrometry determined the theoretical molecular weight of LFBEP-C1 as 48 kDa, and its amino acid coverage was 63%. These findings suggest that the protein LFBEP-C1 with the best lipid-lowering activity was isolated and purified, and its structural characteristics were identified.