Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.1.1.67 (thiopurine methyltransferase)
 551 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thioether S-methyltransferase catalyzes transfer of the methyl group from S-adenosylmethionine to X in compounds of the structure R-X-R', where X may be sulfur, selenium, or tellurium, and R and R' may be various organic groups. To obtain a cDNA clone of thioether S-methyltransferase, a mouse lung cDNA library in lambda gt11 was screened with a 99 base-pair probe obtained by performing the polymerase chain reaction on oligo(dT) primed, reverse transcribed, mouse lung RNA using two degenerate primers designed from partial amino-acid sequences of the enzyme. The entire coding and 3'-untranslated regions were obtained and sequenced. The predicted protein contains 264 amino-acid residues and has a calculated M(r) of 29,460. The amino-acid sequence of thioether S-methyltransferase contains three motifs characteristic of many methyltransferases and has a high level of identity with the amino-acid sequences of nicotinamide N-methyltransferase and phenylethanolamine N-methyltransferase. However, in spite of the fact that they are both mammalian cytosolic sulfur methyltransferases, the sequences of thioether S-methyltransferase and thiopurine S-methyltransferase share little identity.
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PMID:Cloning and base sequence analysis of a cDNA encoding mouse lung thioether S-methyltransferase. 781 83

Escherichia coli cells expressing the tpm gene encoding the bacterial thiopurine methyltransferase (bTPMT) are shown to methylate selenite and (methyl)selenocysteine into dimethylselenide (DMSe) and dimethyldiselenide (DMDSe). E. coli cells expressing tpm from a gene library cosmid clone (harboring a Pseudomonas syringae insert of about 20 kb) also methylated selenate into DMSe and DMDSe. bTPMT is the first methyltransferase shown to be involved in the methylation of these selenium derivatives.
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PMID:Methylation of inorganic and organic selenium by the bacterial thiopurine methyltransferase. 1200 60

Involvement of the bacterial thiopurine methyltransferase (bTPMT) in natural selenium methylation by freshwater was investigated. A freshwater environment that had no known selenium contamination but exhibited reproducible emission of dimethyl selenide (DMSe) or dimethyl diselenide (DMDSe) when it was supplemented with an organic form of selenium [(methyl)selenocysteine] or an inorganic form of selenium (sodium selenite) was used. The distribution of the bTPMT gene (tpm) in the microflora was studied. Freshwater bacteria growing on 10 micro M sodium selenite and 10 micro M sodium selenate were isolated, and 4.5 and 10% of the strains, respectively, were shown by colony blot hybridization to hybridize with a Pseudomonas syringae tpm DNA probe. Ribotyping showed that these strains are closely related. The complete rrs sequence of one of the strains, designated Hsa.28, was obtained and analyzed. Its closest phyletic neighbor was found to be the Pseudomonas anguilliseptica rrs sequence. The Hsa.28 strain grown with sodium selenite or (methyl)selenocysteine produced significant amounts of DMSe and DMDSe. The Hsa.28 tpm gene was isolated by genomic DNA library screening and sequencing. BLASTP comparisons of the deduced Hsa.28 bTPMT sequence with P. syringae, Pseudomonas aeruginosa, Vibrio cholerae, rat, and human thiopurine methyltransferase sequences revealed that the levels of similarity were 52 to 71%. PCR-generated Escherichia coli subclones containing the Hsa.28 tpm open reading frame were constructed. E. coli cells harboring the constructs and grown with sodium selenite or (methyl)selenocysteine produced significant levels of DMSe and DMDSe, confirming that the gene plays a role in selenium methylation. The effect of strain Hsa.28 population levels on freshwater DMSe and DMDSe emission was investigated. An increase in the size of the Hsa.28 population was found to enhance significantly the emission of methyl selenides by freshwater samples supplemented with sodium selenite or (methyl)selenocysteine. These data suggest that bTPMT can play a role in natural freshwater selenium methylation processes.
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PMID:Freshwater bacteria can methylate selenium through the thiopurine methyltransferase pathway. 1283 45