Purification and characterization of a levanbiose-producing levanase from Pseudomonas sp. No. 43.
A levanbiose-accumulating levanase from Pseudomonas sp. No. 43 was purified to a homogeneous state by (NH4)2SO4 fractionation and by chromatography on DEAE-Toyopearl 650 M and phenyl-Toyopearl 650 M columns. The molecular mass and isoelectric point of the enzyme were estimated to be 36 kDa and 5.7 respectively; the optimal pH and temperature for the enzyme reaction were pH 7.0 and 40 degrees C respectively. The purified enzyme was stable in the pH range 6.0-8.0 at 20 degrees C and stable up to 50 degrees C at pH 7.0. The enzyme's activity was inhibited by MnCl2, CoCl2, AlCl3, EDTA and potassium permanganate. The levanase was specific towards the 2, 6-beta-D-fructosidic linkages of levan and did not hydrolyse other polysaccharides among those examined. The enzyme is an exohydrolase of levan and produced levanbiose as a sole product; the limits of hydrolysis of levans from Zymomonas mobilis and Serratia sp. were 65% and 80% respectively.
Jung Kang
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Department of Microbiology, College of Natural Sciences, Pusan National University, Jangjun-Dong 30, Kumjung-gu, Pusan 609-735, Korea.
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D001426:Bacterial Proteins / Q000737:chemistry; D004187:Disaccharides / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability; D005630:Fructans / Q000378:metabolism*; D005632:Fructose / Q000031:analogs & derivatives; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000494:pharmacology; D011549:Pseudomonas / Q000201:enzymology*; D012705:Serratia / Q000737:chemistry; D013379:Substrate Specificity; D013696:Temperature; D017355:Zymomonas / Q000737:chemistry
D001426:Bacterial Proteins; D004187:Disaccharides; D004791:Enzyme Inhibitors; D005630:Fructans; D008670:Metals; C077708:levanbiose; D005632:Fructose; C072599:levan; D006026:Glycoside Hydrolases; C021512:levanase