MMSVLVKEVIEKLRLDIVYGEPELLEKEINIADITRPGLEMTGYFDYYTPERIQLLGMKEWSYLISMPSNSRYEVLKKMFLPETPAVIVARGLVVPEEMLKAARECKIAILTSRAATSRLSGELSSYLDSRLAERTSVHGVLMDIYGMGVLIQGDSGIGKSETGLELVKRGHRLVADDRVDIFAKDEITLWGEPAEILKHLIEIRGVGIIDVMSLYGASAVKDSSQVQLAVYLENYDTHKTFDRLGNNAEELEVSGVAIPRIRIPVKTGRNISVVIEAAAMNYRAKEMGFDATRLFDERLTSLIARNEVQNA 312 HPr(Ser) kinase/phosphorylase Catalyzes the ATP- as well as the pyrophosphate- dependent phosphorylation of a specific serine residue in HPr, a phosphocarrier protein of the phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS). HprK/P also catalyzes the pyrophosphate-producing, inorganic phosphate-dependent dephosphorylation (phosphorolysis) of seryl-phosphorylated HPr (P- Ser-HPr). The two antagonistic activities of HprK/P are regulated by several intracellular metabolites, which change their concentration in response to the absence or presence of rapidly metabolisable carbon sources (glucose, fructose, etc.) in the growth medium. Therefore, by controlling the phosphorylation state of HPr, HPrK/P is a sensor enzyme that plays a major role in the regulation of carbon metabolism and sugar transport: it mediates carbon catabolite repression (CCR), and regulates PTS-catalyzed carbohydrate uptake and inducer exclusion (By similarity). hprK HPr kinase/phosphorylase HPRK_STRR6 spr1270