FIGURE 4.

Enzymatic activity of deletion mutants (Δ-mutants) of LPH. COS-1 cells were transiently transfected. 48 h after transfection, labeled cells were lysed, and proteins were immunoprecipitated. Immunoprecipitates were incubated with lactose and phlorizin, respectively, and the lactase and phlorizin hydrolase activities were measured by determining the concentration of released glucose by HPLC. The enzyme activities of the mutants were compared with those of wild type (WT) LPH. Error bar represents S.E.