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从冬虫夏草液态发酵菌丝体中探测到γ-谷氨酰转肽酶(简称为CSGT)。当以L-谷氨酰-对硝基苯胺和双甘肽为底物时,CSGT的Km和Vmax分别为2.54×10-4mol/L和0.1808mol/L.min。在pH8.0 ～11.0和0 ～20℃条件下,CSGT相对比较稳定;在pH9.0 ～10.0和30℃条件下,CSGT具有最大活力;几种还原剂均能明显激活CSGT,并且较高浓度的Zn2 +、Cu2 +、Hg2 +、Mn2 +等金属离子均能强烈抑制CSGT活性,而K+、Ca2 +、Mg2 +和Na+等对CSGT活性无影响,说明CSGT的活性中心可能含有-SH。
The γ-glutamyl transpeptidase (abbreviated as CSGT) was detected from the liquid fermentation mycelium of Cordyceps sinensis. When L-glutamyl-p-nitroanilide and diglycan were used as substrates, the Km and Vmax of CSGT were 2.54 x 10-4 mol/L and 0.1808 mol/L.min, respectively. CSGT is relatively stable at pH 8.0 to 11.0 and 0 to 20°C; CSGT has maximum activity at pH 9.0 to 10.0 and 30°C; several reducing agents can significantly activate CSGT and have higher concentrations. The metal ions such as Zn2 +, Cu2 +, Hg2 + and Mn2 + can strongly inhibit CSGT activity, while K+, Ca2 +, Mg2 + and Na+ have no effect on CSGT activity, indicating that the active center of CSGT may contain -SH.