Inactivation of vaccinia h1 related phosphatase in the presence of phospho- nomethylating agents

Vaccinia H1-related (VHR) phosphatase was inactivated with phosphonomethyl trifluoromethanesulfonate (PMT), phosphonomethyl pentafluorobenzenesulfonate (PMFB), or phosphonomethyl trifluoroethylsulfonate (PMTres). PMTres produced only about 10% loss of activity; however, both PMT and PMFB produced well over 50% inactivation. Both arsenate and phosphate slowed the inactivation from PMFB in a concentration-dependent manner, suggesting that PMFB modifies a residue at the active site. These results are guiding further studies toward the synthesis of a stable analog of the transiently phosphorylated cysteinyl residue in VHR phosphatase.