Chakraborti, S and Sani, R K and Banerjee, U C and Sobti, R C (2000) Purification and characterization of a novel ?-galactosidase from Bacillus sp MTCC 3088. Journal of Industrial Microbiology and Biotechnology, 24 (1). pp. 58-63. ISSN 1367-5435
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Abstract
An extracellular b-galactosidase which catalyzed the production of galacto-oligosaccharide from lactose was harvested from the late stationary-phase of Bacillus sp MTCC 3088. The enzyme was purified 36.2-fold by ZnCl2 precipitation, ion exchange, hydrophobic interaction and gel filtration chromatography with an overall recovery of 12.7%. The molecular mass of the purified enzyme was estimated to be about 484 kDa by gel filtration on a Sephadex G- 200 packed column and the molecular masses of the subunits were estimated to be 115, 86.5, 72.5, 45.7 and 41.2 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point of the native enzyme, determined by polyacrylamide gel electrofocusing, was 6.2. The optimum pH and temperature were 8 and 60°C, respectively. The Michaelis–Menten constants determined with respect to o-NO2-phenyl-b-D-galactopyranoside and lactose were 6.34 and 6.18 mM, respectively. The enzyme activity was strongly inhibited (68%) by galactose, the end product of lactose hydrolysis reaction. The b-galactosidase was specific for b-D anomeric linkages. Enzyme activity was significantly inhibited by metal ions (Hg2+, Cu2+ and Ag+) in the 1–2.5 mM range. Mg2+ was a good activator. Catalytic activity was not affected by the chelating agent EDTA.
Item Type: | Article |
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Additional Information: | Copyright of this article belongs to Springer Science. |
Uncontrolled Keywords: | purification; extracellular b-galactosidase; o-NO2-phenyl-b-D-galactopyranoside; lactose; Bacillus sp |
Subjects: | Q Science > QR Microbiology |
Depositing User: | Dr. K.P.S.Sengar |
Date Deposited: | 02 Feb 2012 16:31 |
Last Modified: | 02 Feb 2012 16:31 |
URI: | http://crdd.osdd.net/open/id/eprint/849 |
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