虫拟蜡菌硫氧还蛋白还原酶CsTrxR1的基因克隆、酶学特性及功能分析

complete cDNA of thioredoxin reductase encoding gene (CstrxR1) was cloned from Ceriporiosis subvermispora. Its deduced protein consists of 344 amino acid residues with the theoretical molecular mass of 36.9 kDa. The kinetic parameters of rCsTrxR1 with DTNB as substrate were Km = 1535 ± 65 μM, Vmax = 2.6 Μm min-1, Kcat=18 ± 1 s-1, and Kcat/Km=11.7×103 M-1s-1. For the high-cellulase producer Trichoderma reesei D-86271 (RUT-C30), spontaneous mutation is easily occurred under conventional culture process. The mutant could not normally use lactose (but not other sugars) as carbon source, and lost cellulose production ability. Expression plasmid of CstrxR1 gene was constructed using pAg1-H3 as a starting plasmid, and was introduced into T. reesei D-86271 by Agrobacterium tumefaciens-mediated transformation. Unlike the parental strain and control tranformant, the spontaneous mutants from CstrxR1 transformants could produce high level of cellulase, although the lactose utilization was lost. These data indicated that thioredoxin reductase was related with cellulase gene regulation in T. reesei.