Purification
and Characterization of Alginate Lyase from Marine Bacterium Vibrio sp.
QY101
SONG Kai,
YU Wen-Gong, HAN Feng, HAN Wen-Jun, LI Jing-Bao
( Institute of Marine Drug and Food, Ocean University of
China, Qingdao 266003, China )
Abstract Extracellular alginate lyase secreted by
Vibrio sp. QY101, which was isolated from brown algae, was purified to
homogeneity by a combination of ammonium sulfate precipitation, DEAE-Sepharose
Fast Flow anion-exchange chromatography and Superdex 75 gel filtration chromatography.
Its molecular mass was 39 kD as determined by SDS-PAGE analysis. The enzyme had
an optimal temperature of 30 ºC
for its activity, and was most active at pH 7.5. The thermal and pH stability
were 0－30 ºC, and pH 6.5–8.5, respectively. The enzyme
activity was stimulated by 0.5 mol/L NaCl, 1.0 mmol/L Ca2+ or 5.0
mmol/L Mn2+, and inhibited by 5.0 mmol/L Ni2+, 1.0 mmol/L
Fe2+ or 1.0 mmol/L EDTA. Preliminary analysis on substrate
specificity showed that this alginate lyase had activity on both poly-a1,4-L-guluronate and
poly-β1,4-D-mannuronate substrates.
Key words Vibrio sp.; alginate
lyase; purification ; characterizayion
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