Bovine kidney <i>β</i>-mannosidase: purification and characterization

Abstract

Lysosomal beta-mannosidase was purified 160,000-fold in 24% yield from bovine kidney by a four-step purification procedure, which included concanavalin A-Sepharose, immunoaffinity, TSK-butyl and h.p.l.c. cation-exchange chromatography. When analysed by SDS/PAGE and detected by Coomassie Blue or silver staining, the purified enzyme preparation consists of two prominent peptides (100 and 110 kDa) and a third minor peptide (84 kDa). These three peptides are immunologically related and are consistently associated with beta-mannosidase activity in all chromatographic steps. Removal of N-linked carbohydrate from the 84, 100 and 110 kDa peptides decreases their molecular sizes to 75, 86 and 91 kDa respectively. Bovine kidneys lacking beta-mannosidase, activity, acquired from calves affected with beta-mannosidosis, do not contain detectable quantities of the three beta-mannosidase peptides, as judged by monoclonal- and polyclonal-antibody reactivity.