Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The complete chemical synthesis of an E. coli tRNA(Ala) with its specific minor nucleosides, dihydrouridine, ribothymidine and pseudouridine, is reported. The method makes use of protected 2'-O-tertiobutyldimethylsilyl-ribonucleoside-3'-O-(2-cyanoethyl-N- ethyl-N- methyl)phosphoramidites. The exocyclic amino functions of the bases were protected by the phenoxyacetyl group for purines and acetyl for cytosine. The assembling has been performed on a silica support with coupling yield better than 98% within 2 min of condensation. Triethylamine tris-hydrofluoride allowed a clean and complete deprotection of the tBDMS groups. The synthetic tRNA(Ala) has been transcribed into cDNA by reverse transcriptase and sequenced. With E. coli alanyl-tRNA synthetase the alanyl acceptance activity and kcat/Km were 672 pmol/A260 and 6 x 10(4)M-1s-1, respectively.
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PMID:Chemical synthesis of a biologically active natural tRNA with its minor bases. 138 41

A ribonuclease, with a molecular mass of 9 kDa and an N-terminal sequence resembling the sequence of a fragment of tRNA/rRNA cytosine-C5-methylase and a fragment of a alanyl-tRNA synthetase, was isolated from fresh fruiting bodies of the brown oyster mushroom Pleurotus ostreatus. The ribonuclease was purified using a very simple protocol that comprised ion-exchange chromatography on carboxymethyl (CM)-cellulose and affinity chromatography on Affi-gel blue gel. Subsequent gel filtration by fast protein liquid chromatography on Superdex 75 and sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis revealed that the ribonuclease was purified after the first two chromatographic steps. The ribonuclease was adsorbed on CM-cellulose and Affi-gel blue gel. The ribonuclease exhibited the highest activity toward poly A, lower activity toward poly C, slight activity toward poly G, and indiscernible activity toward poly U. The enzyme was stimulated upon exposure to 1 microm Mg2+ and 10 microm Zn2+, but was inhibited by the following ions at 10 mm: Ca2+, Mg2+, Zn2+, Cu2+, Fe2+, Mn2+, and Fe3+. The ribonuclease required a pH of 8.0 and a temperature of 50-70 degrees C to express maximal activity. It had a Km of 60 microm toward yeast tRNA. It lacked mitogenic and HIV-1 reverse transcriptase inhibiting activities, but exerted antiproliferative activity toward leukemia L1210 cells.
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PMID:A low-molecular mass ribonuclease from the brown oyster mushroom. 1594 90