食品科学 ›› 2022, Vol. 43 ›› Issue (2): 151-157.doi: 10.7506/spkx1002-6630-20210110-096

• 生物工程 • 上一篇    下一篇

牛免疫球蛋白G的体外人源唾液酸化及Fc片段的制备

李天慧,陈春旭,陈贵杰,孙怡,曾晓雄   

  1. (1.南京农业大学食品科学技术学院,江苏 南京 210095;2.安徽科技学院食品工程学院,安徽 凤阳 233100)
  • 出版日期:2022-01-25 发布日期:2022-01-29
  • 基金资助:
    “十三五”国家重点研发计划重点专项(2017YFD0400604);国家自然科学基金青年科学基金项目(31901617); 江苏高校优势学科建设工程资助项目(PAPD);安徽省高校自然科学研究项目(KJ2019A0815)

In Vitro Human Sialylation of Bovine Immunoglobulin G and Preparation of Fc Fragment from It

LI Tianhui, CHEN Chunxun, CHEN Guijie, SUN Yi, ZENG Xiaoxiong   

  1. (1. College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; 2. College of Food Engineering, Anhui Science and Technology University, Fengyang 233100, China)
  • Online:2022-01-25 Published:2022-01-29

摘要: 建立将牛免疫球蛋白G(bovine immunoglobulin G,bIgG)糖链末端N-羟乙酰神经氨酸酶切并连接人源N-乙酰神经氨酸(N-acetylneuraminic acid,Neu5Ac)的方法,在实现bIgG转化为人源IgG(human IgG,hIgG)的基础上,研究hIgG可结晶(Fc)片段的制备。结果表明:以170 U/mL神经氨酸酶酶切bIgG(4.0 mg/mL)后,通过β-1,4-半乳糖基转移酶和α-2,6-唾液酸转移酶分别转移半乳糖(galactose,Gal)和Neu5Ac残基,可制备增加8.4 个Gal残基和42 个Neu5Ac残基的hIgG分子。此外,在10.0 mg/mL hIgG、m(木瓜蛋白酶)∶m(hIgG)=0.05、10.0 mmol/L半胱氨酸激活剂、2.0 mmol/L EDTA溶液、pH 7.0条件下,酶解3 h可制得hIgG的较高纯度Fc片段,最终hIgG得率为71.7%,Fc片段得率为20.8%。本研究为bIgG的产品开发和营养价值评价提供科学依据。

关键词: 牛免疫球蛋白G;Fc片段;体外糖基化;唾液酸

Abstract: In the present study, a method for enzymatically digesting N-glycolylneuraminic acid (Neu5Gc) in bovine immunoglobulin G (bIgG) and then ligating the IgG with human N-acetylneuraminic acid (Neu5Ac) was developed to transform bIgG into human IgG (hIgG), and conditions for preparing a crystallizable fragment (Fc) from hIgG were explored. Results showed that hIgG was prepared by digesting Neu5Gc in bIgG (4 mg/mL) with 170 U/mL neuraminidase and subsequently transferring 8.4 galactose (Gal) residues and 42 Neu5Ac residues into the digested IgG with β-1,4-galactosyltransferase (B4GALT1) and α-2,6-sialyltransferase (ST6GAL1), respectively. Further, a highly pure Fc fragment from hIgG was prepared under the conditions: hIgG concentration 10 mg/mL, papain/hIgG ratio 0.05 (m/m), cysteine concentration 10.0 mmol/L, EDTA concentration 2.0 mmol/L, pH 7.0, and hydrolysis time 3 h. The yields of glycosylated hIgG and Fc fragment were 71.7% and 20.8%, respectively. The results of the present study can provide a scientific basis for the development and nutritional evaluation of bIgG-based products.

Key words: bovine immunoglobulin G; Fc fragment; in vitro glycosylation; sialic acid

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