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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1978-5-24
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pubmed:abstractText |
tRNA(guanine-1-)-methyltransferase (EC 2.1.1.31) and tRNA(N2-guanine)-methyltransferase I (EC 2.1.1.32) were isolated from rat liver. The (guanine-1-)-methyltransferase preparation is 6800-fold purified and is free from contaminating methyltransferases or ribonuclease. The molecular weight of (guanine-1-)-methyltransferase is 83 000. Of seven purified Escherichia coli tRNAs examined, only tRNAMetf was utilized as substrate by (guanine-1-)-methyltransferase. The methylation of tRNAMetf is maximally stimulated by 40 mM putrescine with a pH optimum of 8.0. Using E. coli K-12 tRNA, the Km for S-adenosylmethionine is 3 micrometer and Ki for S-adenosylhomocysteine is 0.11 micrometer for (guanine-1-)-methyltransferase. (N2-Guanine-)-methyltransferase is 6200-fold purified and is also free of interfering enzymes. It has a molecular weight of 69 000. E. coli tRNAPhe, tRNAVal and tRNAArg are substrates for this enzyme which introduces a methyl at the 2-amino group of the guanine at position 10 from the 5'-terminus of these tRNAs. The methylation of tRNAPhe is maximally stimulated by 100 micrometer spermidine with a pH optimum of 8.0. (N2-Guanine-)-methyltransferase has a Km for S-adenosylmethionine of 2 micrometer and a Ki for S-adenosylhomocysteine of 23 micrometer with E. coli K-12 tRNA as methyl acceptor.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0006-3002
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
29
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pubmed:volume |
518
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
158-71
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:629973-Animals,
pubmed-meshheading:629973-Guanine,
pubmed-meshheading:629973-Kinetics,
pubmed-meshheading:629973-Liver,
pubmed-meshheading:629973-Male,
pubmed-meshheading:629973-Molecular Weight,
pubmed-meshheading:629973-Putrescine,
pubmed-meshheading:629973-Rats,
pubmed-meshheading:629973-Spermidine,
pubmed-meshheading:629973-Substrate Specificity,
pubmed-meshheading:629973-tRNA Methyltransferases
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pubmed:year |
1978
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pubmed:articleTitle |
Purification and characterization of two tRNA-(guanine)-methyltransferases from rat liver.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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