Linked Life Data

2334705

Source:http://linkedlifedata.com/resource/pubmed/id/2334705

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1990-6-14
pubmed:abstractText
The entire family of ATP analogues that are either mono- or disubstituted with imido and methylene bridges in the polyphosphate chain of ATP have been investigated as substrates and inhibitors of S-adenosylmethionine synthetase (ATP:L-methionine S-adenosyltransferase). The disubstituted analogues adenosine 5'-(alpha,beta:beta,gamma-diimidotriphosphate) (AMPNPNP) and adenosine 5'-(alpha,beta:alpha,beta'-diimidotriphosphate) [AMP(NP)2] have been synthesized for the first time, and a new route to adenosine 5'-(alpha,beta:beta,gamma-dimethylenetriphosphate) (AMPCPCP) has been developed. S-Adenosylmethionine synthetase catalyzes a two-step reaction: the intact polyphosphate chain is displaced from ATP, yielding AdoMet and tripolyphosphate, followed normally, but not obligatorily, by the hydrolysis of the tripolyphosphate to pyrophosphate and orthophosphate. Uniformly, the imido mono- or disubstituted derivatives are both better substrates and better inhibitors than their methylene counterparts. AMPNPNP reacts rapidly to give a single equivalent of product per active site, but subsequent turnovers are at least 1000-fold slower, enabling it to be used to quantify enzyme active site concentrations. In contrast, AMPCPCP is not detectably a substrate (less than 10(-5)% of ATP). AMP(NP)2, a branched isomer of linear AMPNPNP, was not a substrate but was a linear competitive inhibitor, greater than 100 fold more potent than ADP, indicating a reasonable degree of bulk tolerance at the alpha-phosphoryl group binding site.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
13
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1412-6
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Specificity of S-adenosylmethionine synthetase for ATP analogues mono- and disubstituted in bridging positions of the polyphosphate chain.
pubmed:affiliation
Department of Pharmaceutical Chemistry, University of California, San Francisco 94143.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't