Purification and characterization of goat lysosomal beta-mannosidase using monoclonal and polyclonal antibodies

Goat beta-mannosidase was purified 120,000-fold in 26% yield from kidney using concanavalin A-Sepharose chromatography followed by immunoaffinity and cation-exchange chromatography. When analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and visualized by Coomassie Blue staining, the purified enzyme preparation consists of 90- and 100-kDa peptides. Both these peptides react with anti-beta-mannosidase monoclonal antibodies and produce similar electrophoretic peptide patterns when subjected to limited proteolysis. Deglycosylation reduces the size of the 90- and 100-kDa peptides to 86 and 91 kDa, respectively. Goat kidney tissues lacking beta-mannosidase activity, acquired from animals affected with beta-mannosidosis, do not contain detectable quantities of the 90- and 100-kDa peptides as judged by monoclonal antibody reactivity. We postulate that the 90- and 100-kDa peptides represent two related forms of beta-mannosidase.