Abstract
Background: N -acetylglucosaminidase (NAGase) could liberate N -acetylglucosamine (GlcNAc) from GlcNAc-containing oligosaccharides. Trichoderma spp. is an important source of chitinase, particularly NAGase for industrial use. nag1 and nag2 genes encoding NAGase , are found in the genome in Trichoderma spp. The deduced Nag1 and Nag2 shares ~55% homology in Trichoderma virens. Most studies were focus on Nag1 and nag1 previously. Results: The native NAGase (TvmNAG2) was purified to homogeneity with molecular mass of ~68 kDa on SDS-PAGE analysis, and identified as Nag2 by MALDI/MS analysis from an isolate T. virens strain mango. RT-PCR analyses revealed that only nag2 gene was expressed in liquid culture of T. virens , while both of nag1 and nag2 were expressed in T. virens cultured on the plates. TvmNAG2 was thermally stable up to 60 o C for 2 h, and the optimal pH and temperature were 5.0 and 60-65 o C, respectively, using p -nitrophenyl- N -acetyl- β -D-glucosaminide ( p NP-NAG) as substrate. Using colloidal chitin as substrate, the end product catalyzed by TvmNAG2 was GlcNAc, based on HPLC and TLC analyses. The optimal temperature for TvmNAG2 to produce GlcNAc was 40 o C. TvmNAG2 possesses antifungal activity, inhibiting the mycelium growth of Sclerotium rolfsii . And it was resistant to the proteolysis by papain and trypsin. Conclusions: The native Nag2, TvmNAG2 was purified and identified from T. virens strain mango, as well as enzymatic properties. To our knowledge, it is the first report with the properties of native Trichoderma Nag2.
Purification, Identification And Characterization of Nag2 N-Acetylglucosaminidase From Trichoderma Virens Strain Mango