Human aspartylglucosaminidase. A biochemical and immunocytochemical characterization of the enzyme in normal and aspartylglucosaminuria fibroblasts.
Biochem J
; 286 ( Pt 2): 613-8, 1992 Sep 01.
Article
em En
| MEDLINE
| ID: mdl-1530592
ABSTRACT
Aspartylglucosaminidase (AGA, EC 3.5.1.26) is an essential enzyme in the degradation of asparagine-linked glycoproteins. In man, deficient activity of this enzyme leads to aspartylglucosaminuria (AGU), a recessively inherited lysosomal storage disease. Here we used affinity-purified polyclonal antibodies against the native AGA and its denatured subunits to establish the molecular structure and intracellular location of the enzyme in normal and AGU fibroblasts. Inactivation of the enzyme was found to coincide with the dissociation of the heterodimeric enzyme complex into subunits. Although the subunits were not linked by covalent forces, the intrapolypeptide disulphide bridges were found to be essential for the normal function of AGA. AGA was localized into lysosomes in control fibroblasts by both immunofluorescence microscopy and immuno-electron microscopy, whereas in AGU cells the location of antigen was different, suggesting that, owing to the mutation, a missing disulphide bridge, most of the enzyme molecules get retarded in the cis-Golgi region and most probably face intracellular degradation.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Aspartilglucosilaminase
/
Aspartilglucosaminúria
/
Fibroblastos
Limite:
Humans
Idioma:
En
Revista:
Biochem J
Ano de publicação:
1992
Tipo de documento:
Article
País de afiliação:
Finlândia