以L-谷氨酰胺—锌(Ⅱ)配合物为供体酶法制备茶氨酸及其反应机理  

Investigation on Enzymatic Synthesis of L-Theanine with Zinc(Ⅱ)-L-Glutamine Complex and Its Mechanism

作　　者：胡国梅[1] 姚忠[1] 王浩琦[1] 周治[1] 熊强[1] 徐虹[1] 韦萍[1] 

机构地区：[1]南京工业大学食品与轻工学院,江苏南京210009

出　　处：《过程工程学报》2012年第2期283-287,共5页The Chinese Journal of Process Engineering

基　　金：江苏省高校自然科学研究重大基金资助项目(编号:10KJA530014);江苏省科技支撑计划(社会发展)基金资助项目(编号:SBE201078182);江苏省自然科学基金资助项目(编号:(BK2011799)

摘　　要：针对酶法合成茶氨酸中存在的自转肽副反应,合成了L-谷氨酰胺—锌(Ⅱ)配合物Zn(Gln)2,以其为供体、乙胺为受体、枯草芽孢杆菌B.subtilis GGT为催化剂,酶法制备茶氨酸.结果表明,Zn(Gln)2在反应主体相稳定性良好,以Zn(Gln)2为供体可有效抑制自转肽副反应;B.subtilis GGT对Zn(Gln)2和Gln的亲和力常数分别为0.53mmol/L和1.01mmol/L.在Zn(Gln)26.0mmol/L、乙胺200mmol/L及GGT0.5U/mL条件下,经37℃反应2h,茶氨酸浓度最高可达7.38mmol/L,较以Gln为供体时提高了14.42%.To restrain the side reaction of autotranspeptidation, the complex of L-glutamine-Zn（Ⅱ） [Zn（Gln）2] was prepared and used for enzymatic synthesis of theanine via γ-glutamyltranspeptidation （GGT） reaction. The stability and reactivity of Zn（Gln）2 were satisfactory under the reaction conditions. Moreover, autotranspeptidation was restrained effectively when Zn（Gln）2 instead of L-glutamine （Gln） was used as the γ-glutamyl donor. The kinetic parameter Km of B. subtillus GGT toward Zn（Gln）2 and Gln was calculated to be 0.53 and 1.01 mmol/L respectively. Under the conditions of 6 mmol/L Zn（Gln）2, 200 mmol/L ethylamine, and 0.5 U/mL GGT, 7.38 mmol/L of theanine was obtained after incubation at 37℃ for 2 h, indicating an increase of 14.42% compared with that using Gln as the donor substrate.

关 键 词：L-茶氨酸 Γ-谷氨酰转肽酶 L-谷氨酰胺-锌(Ⅱ)配合物 酶法合成 自转肽 

分 类 号：Q556.3[生物学—生物化学]