2.4.1.252 E287A mutant enzyme loses activity in vivo and in vitro 704396 2.4.1.252 E295A mutant enzyme retains residual activity in the in vivo assay 704396 2.4.1.252 H127A retains reduced but significant activity both in vitro and in vivo 704396 2.4.1.252 K211A mutant enzyme loses activity in vivo and in vitro 704396 2.4.1.252 S162A retains reduced but significant activity both in vitro and in vivo 704396