Enzyme I of the phosphotransferase system (cf. EC 18.104.22.168
protein-Npi-phosphohistidine---sugar phosphotransferase). Acts only on histidine residues in specific phosphocarrier proteins of low molecular mass (9.5 kDa) involved in bacterial sugar transport. A similar reaction, where the protein is the enzyme EC 22.214.171.124
pyruvate, water dikinase, is part of the mechanism of that enzyme.