General (non sugar-specific) component of the phosphoenolpyruvate-dependent sugar phosphotransferase system (sugar PTS). This major carbohydrate active-transport system catalyzes the phosphorylation of incoming sugar substrates concomitantly with their translocation across the cell membrane. The phosphoryl group from phosphoenolpyruvate (PEP) is transferred to the phosphoryl carrier protein HPr by enzyme I. Phospho-HPr then transfers it to the PTS EIIA domain. P-Ser-HPr interacts with the catabolite control protein A (CcpA), forming a complex that binds to DNA at the catabolite response elements cre, operator sites preceding a large number of catabolite-regulated genes. Thus, P-Ser-HPr is a corepressor in carbon catabolite repression (CCR), a mechanism that allows bacteria to coordinate and optimize the utilization of available carbon sources. P-Ser-HPr mediates glucose catabolite repression of cry4A toxin expression. Phosphorylation on Ser-45 inhibits the phosphoryl transfer from enzyme I to HPr. The form phosphorylated at the tele nitrogen (N(epsilon)2), instead of the expected pros nitrogen (N(delta)1), of His-14 is not able to transfer its phosphoryl group to the B.subtilis EIIA-Glc domain. This form may be inactive in PTS-catalyzed sugar transport or target an as yet unknown acceptor molecule in an alternative metabolic process. Belongs to the HPr family.