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Purification and some properties of a β-galactosidase from the thermoacidophilic Alicyclobacillus acidocaldarius subsp. rittmannii isolated from Antarctica

Paper ID Volume ID Publish Year Pages File Format Full-Text
18249 42715 2007 8 PDF Available
Title
Purification and some properties of a β-galactosidase from the thermoacidophilic Alicyclobacillus acidocaldarius subsp. rittmannii isolated from Antarctica
Abstract

An intracellular β-galactosidase from a thermoacidophilic Alicyclobacillus acidocaldarius subsp. rittmannii was purified by procedures including precipitation with ammonium sulphate, gel permeation, ion-exchange and affinity chromatography and finally by preparative electrophoresis and some properties of the purified enzyme were determined. The homogenous enzyme had a specific activity of 113 U/mg protein, with a fold purification of 163 and a yield of 8%. The Km and kcat values for ONPG were determined as 8.9 mM and 1074 min−1, respectively in the purified β-galactosidase from A. acidocaldarius subspecies rittmannii. The bacteria produce thermostable β-galactosidase (EC 3.2.1.23) activity, which exhibits its optimum at the neutral pH region. The pH and temperature optima for the purified enzyme are 6.0 and 65 °C, respectively (10 min assay). β-Galactosidase specific activities of crude extracts obtained from bacterial cells grown in the presence and absence of lactose over a period of time (6–40 h) showed that β-galactosidase synthesis seems to be constitutive and increases by increasing time up to 40 h of cultivation. β-Galactosidase activity in the bacteria growing on the medium without lactose was 0.4 U/mg protein and increased up to 0.6 U/mg protein in the cells growing on the medium with lactose at 24 h (an increase by about 33% of its constitutive value), while it was 0.072 and 0.48 U/mg protein, respectively at 12 h (an increase by about 85% of its constitutive value). IPTG was also found to increase β-galactosidase activity over a short period of time. The molecular mass of the purified enzyme determined by gel filtration on FPLC and SDS-PAGE was 165 and 76 kDa, respectively. The β-galactosidase from Alicyclobacillus acidocaldarius subsp. rittmannii is most likely to belong to the glycoside hydrolyse family 42.

Keywords
Alicyclobacillus; β-Galactosidase; Purification; Lactose; PAGE; Optimal pH and temperature; GH-42
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Purification and some properties of a β-galactosidase from the thermoacidophilic Alicyclobacillus acidocaldarius subsp. rittmannii isolated from Antarctica
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 40, Issue 6, 2 May 2007, Pages 1570–1577
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us