Mitsuishi Y, Nitisinprasert S, Saloheimo M, Biese I, Reinikainen T, Claeyssens M, Keränen S, Knowles J K, Teeri T T
VTT Biotechnical Laboratory, Espoo, Finland.
FEBS Lett. 1990 Nov 26;275(1-2):135-8. doi: 10.1016/0014-5793(90)81457-y.
Site directed mutagenesis has been performed to test hypotheses concerning the putative active sites of Trichoderma reesei cellobiohydrolase I and endoglucanase I. It is shown that mutagenesis of the residue E126, previously proposed to be the proton donor in CBHI, did not totally inactivate the enzyme while mutagenesis of the residue E127 in the homologous enzyme EGI resulted in complete loss of activity. These results are compared with those obtained in similar studies of other glucanases and the effects on enzymatic activity of hyperglycosylation of the yeast produced cellulases are discussed.
已进行定点诱变以检验关于里氏木霉纤维二糖水解酶I和内切葡聚糖酶I假定活性位点的假说。结果表明，先前认为是CBHI中质子供体的E126残基诱变并未使该酶完全失活，而同源酶EGI中E127残基诱变导致活性完全丧失。将这些结果与其他葡聚糖酶类似研究中获得的结果进行了比较，并讨论了酵母产生的纤维素酶高糖基化对酶活性的影响。
