Tunicamycin inhibition of N-glycosylation of α-glucosidase from Aspergillus niveus: partial influence on biochemical properties.
Biotechnol Lett
; 32(10): 1449-55, 2010 Oct.
Article
em En
| MEDLINE
| ID: mdl-20490616
ABSTRACT
Treatment of Aspergillus niveus with 30 µg tunicamycin/ml did not interfere with α-glucosidase production, secretion, or its catalytic properties. Fully- and under-glycosylated forms of the enzyme had similar molecular masses, ~56 kDa. Moreover, the absence of N-glycans did not affect either pH optimum (6.0) or temperature optimum (65°C). The K(m) and V(max) values of under- and fully-glycosylated forms of α-glucosidase were similar when assessed for hydrolysis of starch (~0.6 mg/ml, ~350 µmol glucose per min per ml), maltose (~0.54 µmol, ~330 µmol glucose per min per ml) and p-nitrophenyl-α-D -glucopyranoside (~0.54 µmol, ~8.28 µmol p-nitrophenol per min per ml). However, the under-glycosylated form was sensitive to high temperatures probably because, in addition to stabilizing the protein conformation, glycosylation may also prevent unfolded or partially folded proteins from aggregating. Binding assays clearly showed that the under-glycosylated protein did not bind to concanavalin A but has conserve its jacalin-binding property, suggesting that only O-glycans might be intact on the tunicamycin treated form of the enzyme.
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Base de dados:
MEDLINE
Assunto principal:
Aspergillus
/
Proteínas Fúngicas
/
Tunicamicina
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Inibidores Enzimáticos
/
Inibidores de Glicosídeo Hidrolases
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article