α-Mannosidase activity from antibody raised against a glucal antigen

Sixty cell lines of monoclonal antibody were raised against a glucal hapten 1. Among them, Ab 405.4 showed α-mannosidase activity as kcat = 0.19 /day (kcat/kuncat = 110,000). The chemical modification study and pH profile study of this antibody indicated that carboxyl group(s) in the antigen binding site involved in catalytic mechanism.