@article {38368,
	title = {MDP-1 is a new and distinct member of the haloacid dehalogenase family of aspartate-dependent phosphohydrolases},
	journal = {BiochemistryBiochemistry},
	volume = {40},
	year = {2001},
	note = {http://www.ncbi.nlm.nih.gov/pubmed/11601995?dopt=Abstract},
	abstract = {MDP-1 is a eukaryotic magnesium-dependent acid phosphatase with little sequence homology to previously characterized phosphatases. The presence of a conserved motif (Asp-X-Asp-X-Thr) in the N terminus of MDP-1 suggested a relationship to the haloacid dehalogenase (HAD) superfamily, which contains a number of magnesium-dependent acid phosphatases. These phosphatases utilize an aspartate nucleophile and contain a number of conserved active-site residues and hydrophobic patches, which can be plausibly aligned with conserved residues in MDP-1. Seven site-specific point mutants of MDP-1 were produced by modifying the catalytic aspartate, serine, and lysine residues to asparagine or glutamate, alanine, and arginine, respectively. The activity of these mutants confirms the assignment of MDP-1 as a member of the HAD superfamily. Detailed comparison of the sequence of the 15 MDP-1 sequences from various organisms with other HAD superfamily sequences suggests that MDP-1 is not closely related to any particular member of the superfamily. The crystal structures of several HAD family enzymes identify a domain proximal to the active site responsible for important interactions with low molecular weight substrates. The absence of this domain or any other that might perform the same function in MDP-1 suggests an "open" active site capable of interactions with large substrates such as proteins. This suggestion was experimentally confirmed by demonstration that MDP-1 is competent to catalyze the dephosphorylation of tyrosine-phosphorylated proteins.},
	keywords = {Amino Acid Motifs, Amino Acid Sequence, Animals, Aspartic Acid, Catalytic Domain, HUMANS, Hydrolases, Mice, Molecular Sequence Data, Multigene Family, Mutagenesis, Site-Directed, Phosphoprotein Phosphatases, Protein Structure, Tertiary, Protein Tyrosine Phosphatases, Rats, Saccharomyces cerevisiae, sequence alignment, Sequence Homology, Amino Acid},
	author = {J. Selengut}
}
@article {38143,
	title = {Carbonic anhydrase III: the phosphatase activity is extrinsic},
	journal = {Archives of biochemistry and biophysicsArchives of biochemistry and biophysics},
	volume = {377},
	year = {2000},
	note = {http://www.ncbi.nlm.nih.gov/pubmed/10845711?dopt=Abstract},
	type = {10.1006/abbi.2000.1793},
	abstract = {The carbonic anhydrases reversibly hydrate carbon dioxide to yield bicarbonate and hydrogen ion. They have a variety of physiological functions, although the specific roles of each of the 10 known isozymes are unclear. Carbonic anhydrase isozyme III is particularly rich in skeletal muscle and adipocytes, and it is unique among the isozymes in also exhibiting phosphatase activity. Previously published studies provided evidence that the phosphatase activity was intrinsic to carbonic anhydrase III, that it had specificity for tyrosine phosphate, and that activity was regulated by reversible glutathionylation of cysteine186. To study the mechanism of this phosphatase, we cloned and expressed the rat liver carbonic anhydrase III. The purified recombinant had the same specific activity as the carbonic anhydrase purified from rat liver, but it had virtually no phosphatase activity. We attempted to identify an activator of the phosphatase in rat liver and found a protein of approximately 14 kDa, the amount of which correlated with the phosphatase activity of the carbonic anhydrase III fractions. It was identified as liver fatty acid binding protein, which was then purified to test for activity as an activator of the phosphatase and for protein-protein interaction, but neither binding nor activation could be demonstrated. Immunoprecipitation experiments established that carbonic anhydrase III could be separated from the phosphatase activity. Finally, adding additional purification steps completely separated the phosphatase activity from the carbonic anhydrase activity. We conclude that the phosphatase activity previously considered to be intrinsic to carbonic anhydrase III is actually extrinsic. Thus, this isozyme exhibits only the carbon dioxide hydratase and esterase activities characteristic of the other mammalian isozymes, and the phosphatase previously shown to be activated by glutathionylation is not carbonic anhydrase III.},
	keywords = {Animals, Carbonic Anhydrases, Chromatography, High Pressure Liquid, Cloning, Molecular, Enzyme Activation, Glutathione, Kinetics, Liver, Male, Muscles, Phosphoric Monoester Hydrolases, Precipitin Tests, Rabbits, Rats, Rats, Inbred F344, Recombinant Proteins, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Time factors},
	author = {Kim, G. and J. Selengut and Levine, R. L.}
}
@article {49715,
	title = {Pseudogenes for human small nuclear RNA U3 appear to arise by integration of self-primed reverse transcripts of the RNA into new chromosomal sites.},
	journal = {Cell},
	volume = {32},
	year = {1983},
	month = {1983 Feb},
	pages = {461-72},
	abstract = {<p>We find that both human and rat U3 snRNA can function as self-priming templates for AMV reverse transcriptase in vitro. The 74 base cDNA is primed by the 3{\textquoteright} end of intact U3 snRNA, and spans the characteristically truncated 69 or 70 base U3 sequence found in four different human U3 pseudogenes. The ability of human and rat U3 snRNA to self-prime is consistent with a U3 secondary structure model derived by a comparison between rat U3 snRNA and the homologous D2 snRNA from Dictyostelium discoideum. We propose that U3 pseudogenes are generated in vivo by integration of a self-primed cDNA copy of U3 snRNA at new chromosomal sites. We also consider the possibility that the same cDNA mediates gene conversion at the 5{\textquoteright} end of bona fide U3 genes where, over the entire region spanned by the U3 cDNA, the two rat U3 sequence variants U3A and U3B are identical.</p>},
	keywords = {Animals, Base Sequence, DNA, genes, HUMANS, Nucleic Acid Conformation, Rats, Recombination, Genetic, Repetitive Sequences, Nucleic Acid, RNA, RNA, Small Nuclear, RNA-Directed DNA Polymerase, Templates, Genetic, Transcription, Genetic},
	issn = {0092-8674},
	author = {Bernstein, L B and Mount, S M and Weiner, A M}
}
