Purification and properties of Bacillus subtilis SA-22 endo-1, 4-beta-D-mannanase.
beta-mannanase (EC 3.2.1.78) from Bacillus subtilis SA-22 was purified successively by ammonium sulfate precipitation, hydroxyapatite chromatography, Sephadex G-75 gel filtration and DEAE-52 anion-exchange chromatography. Through these steps, the enzyme was concentrated 30.75-fold with a recovery rate of 23.43%, with a specific activity of 34780.56 u/mg. Molecular weight of the enzyme was determined to be 38 kD by SDS-PAGE and 34 kD by gel filtration. The results revealed that the optimal pH value for the enzyme was 6.5 and the optimal temperature was 70 degrees C. The enzyme is stable between pH 5 to 10. The enzyme remained most of its activity after a treatment of 4 h at 50 degrees C, but lost 25% of activity at 60 degrees C for 4 h, lost 50% of activity at 70 degrees C for 3 h. The enzyme activity was strongly inhibited by Hg2+. The Michaelis constants (Km) were measured as 11.30 mg/mL for locust bean gum and 4.76 mg/mL for konjac powder, while Vmax for these two polysaccharides were 188.68 (micromol x mL(-1) x min(-1)) and 114.94 (micromol x mL(-1) x min(-1)), respectively.
Yu
Hong-Ying
HY
Faculty of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510090 2, China.
Sun
Yuan-Ming
YM
Wang
Wei-Jun
WJ
Yang
Yue-Sheng
YS
Yang
You-Hui
YH
D001412:Bacillus subtilis / Q000201:enzymology*; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008361:Mannosidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D008628:Mercury / Q000494:pharmacology
D008361:Mannosidases; C041867:endo-1,4-beta-D-mannanase; D008628:Mercury