PURIFICATION AND CHARACTERIZATION OF N-GLYCANASE, A CONCANAVALIN-A BINDING-PROTEIN FROM JACKBEAN (CANAVALIA-ENSIFORMIS)

Removal of the N-glycan from the concanavalin A (Con A) glycoprotein p recursor is a key step in its conversion into an active lectin. N-Glyc anase (EC 3.5.1.52), the enzyme from jackbean catalysing this process, has been purified to homogeneity as judged by native PAGE. One of the purification steps is binding of the enzymic activity to Con A-Sephar ose and its elution by methyl alpha-mannoside. On SDS/PAGE the princip al components were found to be 78 kDa, 74 kDa, 54 kDa, 32 kDa and 30 k Da polypeptides. These did not react with Con A on an affinity blot. C leveland mapping indicated that some of these polypeptides had related primary structures. The enzyme has a broad pH optimum in the region o f 5.0.