[Purification and properties of a thermostable chitinase from thermophilic fungus Thermomyces lanuginosus].
A thermostable extracellular chitinase from culture supernatant of a thermophilic fungus Thermomyces lanuginosus was purified to SDS-PAGE homogeneity, by using ammonium sulfate fraction, DEAE-Sepharose Fast flow chromatography, Phenyl-Sepharose Fast Flow chromatography. A molecular mass of the purified enzyme was between 48-49.8 kD determined by SDS-PAGE and gel filtration chromatography. The chitinase exhibited optimum catalytic activity at pH 4.5 and 55 degrees C respectively. It was thermostable at 50 degrees C and retained 24% activity after 20 min at 70 degrees C. The half life time of the enzyme at 65 degrees C was 25 min. Different metal ions showed different effects on the chitinase activity. Ca2+, Ba2+, Na+, K+ enhanced the enzyme activity, whereas Fe2+, Ag+, Hg2+, Cu2+ caused obvious inhibition. The Km and Vmax values of chitinase on colloidal chitin were 9.56 mg/mL and 22.12 micromol/min respectively. The chitinase showed antifungal activity aginst tested fungi to different degree.
Department of Environmental Biology, Shandong Agricultural University, Tai'an 271018, China. runfangg@163.com
Run-fang
RF
Guo
Duo-chuan
DC
Li
Rong
R
Wang
D000595:Amino Acid Sequence; D001203:Ascomycota / Q000201:enzymology*; D002688:Chitinases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D004789:Enzyme Activation; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D013696:Temperature
D002688:Chitinases