Linked Life Data

3064808

Source:http://linkedlifedata.com/resource/pubmed/id/3064808

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
17
pubmed:dateCreated
1989-3-23
pubmed:abstractText
Interactions between Escherichia coli arginyl-tRNA synthetase and its substrates were extensively studied and distinctly demonstrated. Various approaches such as equilibrium dialysis, fluorescence titration, and substrate protection against heat inactivation of the enzyme were used for these studies. In the absence of other substrates, the equilibrium dissociation constants for arginine, ATP, and the cognate tRNA were about 70 microM, 0.85 mM, and 0.45 microM, respectively, at pH 7.5, in Tris buffer. The binding of arginine to the enzyme was affected neither by the presence of tRNA nor by the presence of ATP but was considerably enhanced when ATP and tRNA were both present at saturating concentrations. The dissociation constant in this case (about 16 microM) was very close to the Km (12 microM) for arginine during aminoacylation. The binding of ATP (the equilibrium dissociation constant KD approximately 0.85 mM) was not affected by the presence of arginine but was depressed in the presence of tRNA (KD became 3 mM). Arginyl-tRNA showed a dissociation constant of (4-5) X 10(-7) M which was not affected by the presence of a single other substrate. Possible explanations for the high Km for tRNA in the aminoacylation are discussed. Our results indicated pronounced interactions between substrates mediated by the enzyme under catalytic conditions. Periodate oxidation did not alter the tRNA binding to the enzyme. The oxidized tRNA still afforded protection against heat inactivation of the enzyme.
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
23
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6348-53
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Interactions between Escherichia coli arginyl-tRNA synthetase and its substrates.
pubmed:affiliation
Shanghai Institute of Biochemistry, Academia Sinica, China.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't