牛免疫球蛋白G的体外人源唾液酸化及Fc片段的制备  

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

作　　者：李天慧 陈春旭 陈贵杰 孙怡[1] 曾晓雄[1] LI Tianhui;CHEN Chunxun;CHEN Guijie;SUN Yi;ZENG Xiaoxiong(College of Food Science and Technology,Nanjing Agricultural University,Nanjing 210095,China;College of Food Engineering,Anhui Science and Technology University,Fengyang 233100,China)

机构地区：[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　　处：《食品科学》2022年第2期151-157,共7页Food Science

基　　金：“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)。

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。In the present study, a method for enzymatically digesting N-glycolylneuraminic acid(Neu5 Gc) in bovine immunoglobulin G(bIgG) and then ligating the IgG with human N-acetylneuraminic acid(Neu5 Ac) 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 Neu5 Gc in bIgG(4 mg/mL) with 170 U/mL neuraminidase and subsequently transferring 8.4 galactose(Gal) residues and 42 Neu5 Ac residues into the digested IgG with β-1,4-galactosyltransferase(B4 GALT1) and α-2,6-sialyltransferase(ST6 GAL1), 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.

关 键 词：牛免疫球蛋白G Fc片段 体外糖基化 唾液酸 

分 类 号：S896.4[农业科学—特种经济动物饲养]