Histidine phosphatase domain found in a functionally diverse set of proteins, mostly phosphatases; contains a His residue which is phosphorylated during the reaction.
Catalytic domain of a functionally diverse set of proteins, most of which are phosphatases. The conserved catalytic core of this domain contains a His residue which is phosphorylated in the reaction. This set of proteins includes cofactor-dependent and cofactor-independent phosphoglycerate mutases (dPGM, and BPGM respectively), fructose-2,6-bisphosphatase (F26BP)ase, Sts-1, SixA, histidine acid phosphatases, phytases, and related proteins. Functions include roles in metabolism, signaling, or regulation, for example F26BPase affects glycolysis and gluconeogenesis through controlling the concentration of F26BP; BPGM controls the concentration of 2,3-BPG (the main allosteric effector of hemoglobin in human blood cells); human Sts-1 is a T-cell regulator; Escherichia coli Six A participates in the ArcB-dependent His-to-Asp phosphorelay signaling system; phytases scavenge phosphate from extracellular sources. Deficiency and mutation in many of the human members result in disease, for example erythrocyte BPGM deficiency is a disease associated with a decrease in the concentration of 2,3-BPG. Clinical applications include the use of prostatic acid phosphatase (PAP) as a serum marker for prostate cancer. Agricultural applications include the addition of phytases to animal feed.
Comment:The catalytic core includes a His group which is phosphorylated during phosphoryl transfer as well as two key Arg residues and an additional His residue which are hydrogen bonded to the phospho group before, during, and after transfer.