title: Molecular cloning of a cDNA for the human phospholysine phosphohistidine inorganic pyrophosphate phosphatase.
abstract: We previously reported the isolation from bovine liver of a novel 56-kDa inorganic pyrophosphatase named phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPPase). It 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. In this study, we determined the partial amino acid sequence of the purified bovine LHPPase. To investigate whether humans have the same enzyme, we 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. The recombinant protein was produced in E. coli. Its ability to hydrolyze oxygen-phosphorus bonds and nitrogen-phosphorus bonds was confirmed. The enzymatic characteristics of this human protein were similar to those of purified bovine LHPPase. Thus, we concluded that the cDNA encoded the human counterpart of bovine LHPPase.
authors.affiliation: Department of Biochemistry, Saga Medical School, Nabeshima 5-1-1, Saga-shi, Saga 849-8501, Japan. yokoi@uiuc.edu
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Yokoi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hiraishi
authors.forename: Kenji
authors.initials: K
authors.lastname: Izuhara
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D003001:Cloning, Molecular; D018076:DNA, Complementary; D011756:Diphosphates / Q000378:metabolism; D004164:Diphosphonates / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005333:Fetus / Q000201:enzymology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D043564:Inorganic Pyrophosphatase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009941:Organomercury Compounds / Q000494:pharmacology; D011993:Recombinant Fusion Proteins; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
chemical_list: C400327:4-CMPS; D018076:DNA, Complementary; D011756:Diphosphates; D004164:Diphosphonates; D004791:Enzyme Inhibitors; D009941:Organomercury Compounds; D011993:Recombinant Fusion Proteins; C016514:imidodiphosphonic acid; D043564:Inorganic Pyrophosphatase