Detection and Partial Characterization of γ-glutamyltranspeptidase from Cordyceps sinensis Mycelia / 中国生物工程杂志

ABSTRACT

γ-glutamyltranspeptidase was detected from the cultured mycelia of Cordyceps sinensis (CSGT). Km and Vmax of CSGT was 2.54×10-4 mol/L and 0.1808 mol/L·min respectively when L-glutamic acid 5-(4-nitroanilide) (GpNA) and glycyglycine was used as its substrate. CSGT was stable from pH 8.0 to 11.0 and at or below 20℃. It was optimally active at pH 9.0～10.0 and 30℃. A series of reducing reagents could activate CSGT, and metal cations such as Zn2+, Cu2+, Hg2+ , Mn2+ inhibited strongly activity of the enzyme, but K+, Ca2+, Mg2+ and Na+ at high concentrations had no effect on its activity, indicating that its active center could contain -SH.