Purification and characterization of a thermostable α-amylase produced by the fungus Paecilomyces variotii.
Carbohydr Res
; 345(16): 2348-53, 2010 Nov 02.
Article
em En
| MEDLINE
| ID: mdl-20850111
ABSTRACT
An α-amylase produced by Paecilomyces variotii was purified by DEAE-cellulose ion exchange chromatography, followed by Sephadex G-100 gel filtration and electroelution. The α-amylase showed a molecular mass of 75 kDa (SDS-PAGE) and pI value of 4.5. Temperature and pH optima were 60°C and 4.0, respectively. The enzyme was stable for 1 h at 55°C, showing a t50 of 53 min at 60°C. Starch protected the enzyme against thermal inactivation. The α-amylase was more stable in alkaline pH. It was activated mainly by calcium and cobalt, and it presented as a glycoprotein with 23% carbohydrate content. The enzyme preferentially hydrolyzed starch and, to a lower extent, amylose and amylopectin. The K(m) of α-amylase on Reagen® and Sigma® starches were 4.3 and 6.2 mg/mL, respectively. The products of starch hydrolysis analyzed by TLC were oligosaccharides such as maltose and maltotriose. The partial amino acid sequence of the enzyme presented similarity to α-amylases from Bacillus sp. These results confirmed that the studied enzyme was an α-amylase ((1â4)-α-glucan glucanohydrolase).
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Temperatura
/
Paecilomyces
/
Alfa-Amilases
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article