Open AccessUse of a monoclonal antibody to distinguish between precursor and mature forms of human lysosomal α‐glucosidase
Author(s) -
OUDE ELFERINK Ronald P. J.,
STRIJLAND Anneke,
SURYA Inge,
BROUWERKELDER Elisabeth M.,
KROOS Marian,
HILKENS John,
HILGERS Jo,
REUSER Arnold J. J.,
TAGER Joseph M.
Publication year - 1984
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1984.tb08033.x
Subject(s) - monoclonal antibody , leupeptin , endocytosis , microbiology and biotechnology , antibody , clone (java method) , biochemistry , chemistry , biology , epitope , enzyme , cell , immunology , protease , dna
The maturation of lysosomal α‐glucosidase in cultured human skin fibroblasts was studied using a monoclonal antibody that distinguishes between the precursor and mature forms of the enzyme. 1. Monoclonal antibodies against α‐glucosidase isolated from placenta were produced by the hybridoma technique [Hilkens et al. (1981) Biochim. Biophys. Acta 678 , 7–11]. One of these monoclonal antibodies, that synthesized by clone 43G8, reacts with the mature forms, but not with the precursor form of α‐glucosidase isolated from urine. 2. By means of pulse‐labelling studies, it could be shown that monoclonal antibody 43G8 does not react with either the intracellular or the secreted precursor of α‐glucosidase from cultured human skin fibroblasts. However, the antibody does react with the intermediate and mature forms of α‐glucosidase. 3. Endocytosis of the precursor of α‐glucosidase from urine by fibroblasts is followed by its conversion to a form with lower molecular mass. 4. After endocytosis urinary precursor α‐glucosidase is converted to a form that binds to monoclonal antibody 43G8. The t 1/2 for this conversion is 2 h. The conversion is inhibited by addition of leupeptin to the culture medium. 5. It is concluded that a thiol proteinase is involved in the maturation of α‐glucosidase in fibroblasts and the appearance of the antigenic determinant for 43G8.