Purification of chitinase and antagonism of Streptomyces violaceusniger towards wood rotting fungi

Purification and characterization of an extracellular chitinase from antagonistic Streptomyces violaceusniger

Anand Nagpure and Rajinder K. Gupta

Journal of Basic Microbiology, 2012, 52, 1-11

The actinomycetes Streptomyces violaceusniger showed strong antagonistic activity against various tested wood rotting fungi. An extracellular chitinase, produced by Streptomyces violaceusniger, was purified in the following procedures: ammonium sulfate precipitation and chromatographic separation of Q Sepharose. The molecular mass of the purified chitinase was 48 kDa, estimated by a sodium dodecyl sulfatepolyacrylamide gel electrophoresis. Chitinase was optimally active at pH of 5.0, and at 50°C. It retains almost 100% activity in the pH range of 5.0. This chitinase has a high thermal tolerance and retained 100% of its activity at 50°C. Enzyme activity was inhibited by Hg²⁺ and Ag+ cations, but was not substantially inhibited by the K⁺ cation nor the chelating agent EDTA. The apparent Km and Vmax values for pNP-(GlcNAc)₂ were 0.1426 mM and 6.6 U/mg, respectively, at 37°C. The 48 kDa chitinase of Streptomyces violaceusniger is an exo-type enzyme, because maximum activity was obtained with chromogenic substrate pNP-(GlcNAc)₂.
http://onlinelibrary.wiley.com/doi/10.1002/jobm.201100648/abstract