Purification, characterization, and gene cloning of a new cold-adapted ß-galactosidase from Erwinia sp. E602 isolated in northeast China.
J Dairy Sci
; 101(8): 6946-6954, 2018 Aug.
Article
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| MEDLINE
| ID: mdl-29859695
ABSTRACT
ß-Galactosidases are widely used in industry for elimination of lactose from milk products. A new ß-galactosidase was obtained from bacterial strain Erwinia sp. E602, newly isolated in northeast China. The enzyme was purified with the methods of ammonium sulfate fractionation, ion exchange, and gel filtration chromatography for further study of the enzymatic characteristics. The purified enzyme had a molecular weight of near 110 kDa. The optimum reaction temperature and pH of this enzyme was determined to be 40°C and 7.0, respectively, indicating that this enzyme was a mesophilic neutral ß-galactosidase. Furthermore, the enzyme retained near 10% of the activity at 0°C, which also suggested its cold-adapted property. Kinetics of the ß-galactosidase was studied, and the Km (Michaelis constant) and Vmax (maximum enzymatic reaction rate) of this enzyme were 0.21 mmol/L and 263.16 µmol/mg per minute, respectively. The effects of metal ions on the enzymatic activity and the lactose hydrolysis efficiency in milk, as well as its trans-glycosylation activity, were studied in this work. The ß-galactosidase coding gene was cloned to be a 3-kb length fragment, which shared at most 81% of identity with the published sequences in NCBI Blast database (https//blast.ncbi.nlm.nih.gov). Results in this work suggested it is a new ß-galactosidase and it has potential to be used in dairy and food processing.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Clonación Molecular
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Beta-Galactosidasa
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Erwinia
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Lactosa
Límite:
Animals
País/Región como asunto:
Asia
Idioma:
En
Revista:
J Dairy Sci
Año:
2018
Tipo del documento:
Article
País de afiliación:
China
Pais de publicación:
EEUU
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ESTADOS UNIDOS
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ESTADOS UNIDOS DA AMERICA
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EUA
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UNITED STATES
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UNITED STATES OF AMERICA
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US
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USA