Isolation and Characterization of a Novel Sialoglycopeptide Promoting Osteogenesis from <i>Gadus morhua</i> Eggs

• Main Authors: Zhiliang Hei, Meihui Zhao, Yingying Tian, Hong Chang, Xuanri Shen, Guanghua Xia, Jingfeng Wang
• Format: Article
• Language: English
• Published: MDPI AG 2019-12-01
• Series: Molecules
• Subjects: <i>gadus morhua</i> eggs; sialoglycopeptide; osteogenesis; structure characterization
• Online Access: https://www.mdpi.com/1420-3049/25/1/156

<i>Gadus morhua</i> eggs contain several nutrients, including polyunsaturated fatty acids, lecithin and glycoproteins. A novel sialoglycopeptide from the eggs of <i>G. morhua</i> (<i>Gm</i>-SGPP) was extracted with 90% phenol and purified by Q Sepharose Fast Flow (QFF) ion exchange chromatography, followed by S-300 gel filtration chromatography. <i>Gm</i>-SGPP contained 63.7% carbohydrate, 16.2% protein and 18.6% N-acetylneuraminic acid. High-performance size exclusion chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that <i>Gm</i>-SGPP is a 7000-Da pure sialoglycopeptide. &#946;-elimination reaction suggested that <i>Gm</i>-SGPP contained N-glycan units. Amino acid N-terminal sequence analysis indicated the presence of Ala-Ser-Asn-Gly-Thr-Gln-Ala-Pro amino acid sequence. Moreover, N-glycan was connected at the third Asn location of the peptide chain through GlcNAc. <i>Gm</i>-SGPP was composed of D-mannose, D-glucuronic acid and D-galactose. Fourier transform-infrared spectroscopy (FT-IR), ¹H-nuclear magnetic resonance spectroscopy (¹H-NMR) and methylation analysis were performed to reveal the structure profile of <i>Gm</i>-SGPP. In vitro results showed that the proliferation activity of MC3T3-E1 cells was significantly promoted by <i>Gm</i>-SGPP. In vivo data revealed that <i>Gm</i>-SGPP increased the calcium and phosphorus content of tibias and promoted longitudinal bone growth in adolescent rats.