Phospholysine Phosphohistidine Inorganic Pyrophosphate Phosphatase (LHPP)

LHPPase is a unique enzyme that hydrolyzes not only oxygen-phosphorus bonds in inorganic pyrophosphate but also nitrogen-phosphorus bonds in phospholysine, phosphohistidine and imidodiphosphate in vitro. To investigate whether humans have the same enzyme, isolated a cDNA clone from a HeLa cell cDNA library that encodes for the human homologue of LHPPase. Although its sequence does not include the consensus sequence of a typical inorganic pyrophosphatase, it does contain a similar sequence of the active site in other phosphatases such as protein-tyrosine phosphatase, dual-specific phosphatase and low molecular weight acid phosphatase. Human LHPPase was highly expressed in the liver and kidney, and moderately in the brain.