Intra- and extracellular forms of ethanol-modified O-underglycosylated galactose oxidase.
Arch Biochem Biophys
; 275(1): 130-9, 1989 Nov 15.
Article
em En
| MEDLINE
| ID: mdl-2817892
The effect of ethanol and tunicamycin on synthesis and secretion of galactose oxidase was studied in resting cells of Dactylium dendroides. Ethanol promoted an overall decrease in both intra- and extracellular enzyme levels to the same extent that it inhibited [14C]glucosamine incorporation into total protein. The carbohydrate content of the intracellular enzyme was also depressed (44%) with a simultaneous decrease in O-Ser linked oligosaccharides. The intracellular galactose oxidase obtained after exposure of mycelia to ethanol plus tunicamycin lost 86% of its carbohydrate moieties, whereas the extracellular form lost only 35%. In both cases, residual sugar moieties were not eliminated by mild alkaline treatment. These data suggest that ethanol affects O-glycosylation of galactose oxidase. O-Underglycosylation did not affect the S0.5 values for galactose but diminished the molar catalytic activity. The absence of O-Ser/Thr-linked saccharides turned the intracellular enzyme into a form more susceptible to proteolysis than that devoid of N-linked sugars (tunicamycin-treated). O-Underglycosylation had a significant effect on the renaturation-reactivation of the enzyme after denaturation with 2.4 M Gdn-HCl.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Polyporaceae
/
Basidiomycota
/
Processamento de Proteína Pós-Traducional
/
Etanol
/
Galactose Oxidase
/
Glucosamina
Idioma:
En
Revista:
Arch Biochem Biophys
Ano de publicação:
1989
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Estados Unidos