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Publications (2)3.22 Total impact

  • Rentao Yu, Lushan Wang, Xinyuan Duan, Peiji Gao
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    ABSTRACT: A culture-independent strategy has been developed for investigation of cellulases in moldy silage. By the qualitative differences in the adsorption of cellulases on lingo-cellulosics, a new cellobiohydrolase (CBH) with apparent molecular mass of 194 kDa was isolated and characterized. The entire extracellular proteins of silage were separated by two-dimensional gel electrophoresis, and five potential endoglucanases were identified by activity staining. These results demonstrate the feasibility of direct screening cellulases from environment without microorganism cultivation and this strategy could be expected to facilitate the research of uncultured microorganisms.
    Biotechnology Letters 08/2007; 29(7):1037-43. · 1.85 Impact Factor
  • Shuyan Liu, Xinyuan Duan, Xuemei Lu, Peiji Gao
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    ABSTRACT: A novel thermophilic endoglucanase (EGt) was extracted from a mesophilic fungus (Fusarium oxysporum L19). We invoked conventional kinetic enzyme reactions using the sodium salt of carboxymethyl cellulose (CMC-Na) as substrate. EGt displayed optimal activity at 75°C when kept running 30 min in the temperature range of 30–85°C. Thermal stability curve measured at 70°C suggested that its half-life time is 15.1 min. The activity was enhanced in the presence of Co2+ or Mg2+ but inhibited by Pb2+ and Fe3+. Moreover, N-bromosuccinimide (NBS) modification resulted in a complete loss of EGt activity, suggesting that tryptophan residues may be involved in the enzyme active site. Amino acid composition analysis demonstrated that EGt contains more proline residues. EGt lacks activity towards p-nitrophenyl cellobiose (pNPC). The N-terminal amino acid sequence of EGt is SYRVPAANGFPNPDASQEKQ, and the gene of EGt was sequenced and analyzed. Extensive sequence alignments failed to show any homology between EGt and any known endoglucanases. This is the first report addressing the thermal adaptation of a cellulolytic enzyme from the mesophilic fungus F. oxysporum. Maybe the expression of multiple isoenzyme in an organism helps it adapt to complex living environments.
    Chinese Science Bulletin 12/2005; 51(2):191-197. · 1.37 Impact Factor