3.2.1.186 4.5 5 recombinant His-tagged enzyme 3.2.1.186 5 - assay at 3.2.1.186 5 - native enzyme 3.2.1.186 5 - reaction with p-nitrophenyl beta-D-glucoside or torvoside H 3.2.1.186 5 5.5 substrate: protogracillin