title: Molecular cloning of cDNAs for human fibroblast nucleotide pyrophosphatase.
abstract: Nucleotide pyrophosphatase (NPPase) activity is markedly elevated in cultured skin fibroblasts from patients of Lowe's syndrome. cDNA clones encoding the NPPase were isolated using synthetic oligonucleotide probes designed on the basis of partial amino acid sequence of the enzyme purified from human placenta. The complete sequences of these clones yielded a merged sequence of 3508 bases. The polypeptide chain of the enzyme was deduced to comprise 873 amino acids with a calculated molecular weight of 99,703 and had the characteristics of a class II transmembrane protein. Ten potential N-glycosylation sites were detected in the protein. RNA blot analysis showed that human fibroblasts contain two minor mRNAs of 7.0 and 8.2 kb, respectively, in addition to a major 3.6-kb species that coincides with the merged cDNA in size. A computer search of a nucleotide sequence data-base revealed that plasma cell membrane glycoprotein PC-1, whose function was unknown at the time, is identical with the NPPase. Comparison of the amino acid sequence of the NPPase with the active site sequence of bovine 5'-nucleotide phosphodiesterase allowed the assignment of a putative active site domain to the central region of the COOH-terminal extracellular domain of the NPPase. The gene for human NPPase was localized to chromosome 6 at q22-q23 by in situ hybridization with a fragment of the NPPase cDNA.
authors.affiliation: Department of Biotechnology, Faculty of Engineering, Kyoto Sangyo University, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Funakoshi
authors.forename: H
authors.initials: H
authors.lastname: Kato
authors.forename: K
authors.initials: K
authors.lastname: Horie
authors.forename: T
authors.initials: T
authors.lastname: Yano
authors.forename: Y
authors.initials: Y
authors.lastname: Hori
authors.forename: H
authors.initials: H
authors.lastname: Kobayashi
authors.forename: T
authors.initials: T
authors.lastname: Inoue
authors.forename: H
authors.initials: H
authors.lastname: Suzuki
authors.forename: S
authors.initials: S
authors.lastname: Fukui
authors.forename: M
authors.initials: M
authors.lastname: Tsukahara
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D005260:Female; D005347:Fibroblasts / Q000201:enzymology*; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D010727:Phosphoric Diester Hydrolases / Q000235:genetics; D010920:Placenta / Q000201:enzymology; D011755:Pyrophosphatases / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D010727:Phosphoric Diester Hydrolases; C065962:ectonucleotide pyrophosphatase phosphodiesterase 1; D011755:Pyrophosphatases; C021899:nucleotide pyrophosphatase