Linked Life Data

7028092

Source:http://linkedlifedata.com/resource/pubmed/id/7028092

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
16
pubmed:dateCreated
1982-1-9
pubmed:abstractText
A new activity of Escherichia coli and yeast phenylalanyl-tRNA synthetases, the conversion adenosine 5' -triphosphate into diadenosine 5' ,5"' -P(1) ,P(4) -tetraphosphate, is reported. This activity is followed by (31)P NMR and chromatography on poly(ethylenimine)-cellulose. It is revealed by the addition of ZnCl2 to a reaction mixture containing the enzyme, ATP-Mg(2+), L-phenylalanine, and pyrophosphatase It reflects the reaction enzyme-bound phenylalanyl adenylate with ATP instead of PPi and strongly depends on the hydrolysis of pyrophosphate in the assay medium. The zinc dependence of this reaction parallels that of the inhibition of tRNA(phe) aminoacylation which is described in the accompanying paper [Mayaux, J. F., & Blanquet, S. (1981) Biochemistry (preceding paper in this issue)]. In the presence of an unlimiting pyrophosphatase activity, diadenosine tetraphosphate synthesis by E. coli and yeast phenylalanyl-tRNA synthetases occurs at maximal rates of 0.5 and 2 s-1, respectively (37 degrees C, pH 7.8, 150 mM KC1, 5 mM ATP, 10 mM MgCl2, 2 mM L-phenylalanine, and 80 muM ZnCl2). Under identical experimental conditions, E coli isoleucyl-, methionyl-, and tyrosyl-tRNA synthetases produce small amounts of diadenosine tetraphosphate at rates 2 or 3 orders of magnitude lower than that achieved by phenylalanyl-tRNA synthetase. In the case of E. coli phenylalanyl-tRNA synthetase, it is shown that the diadenosine tetraphosphate synthetase activity is accompanied by a diadenosinetetraphosphatase activity. This activity, actually supported by phenylalanyl-tRNA synthetase, is responsible for the appearance of ADP in the assay medium. It requires also the presence of both ZnCl2 and L-phenylalanine. The formation of ADP from diadenosine tetraphosphate and its reaction with enzyme-bound aminoacyl adenylate account for the appearance in the reaction mixture of diadenosine 5' ,5"' -P(1) ,P(3)-triphosphate, after that of diadenosine tetraphosphate. The significance of these findings in the context of the role of diadenosine tetraphosphate in controlling cellular growth is discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4654-62
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1981
pubmed:articleTitle
Zinc(II)-dependent synthesis of diadenosine 5', 5"' -P(1) ,P(4) -tetraphosphate by Escherichia coli and yeast phenylalanyl transfer ribonucleic acid synthetases.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't