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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
41
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pubmed:dateCreated |
1996-11-27
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pubmed:abstractText |
4-Chlorobenzoate:coenzyme A ligase (4-CBA:CoA ligase) catalyzes the first step of the 4-CBA degradation pathway of Pseudomonas sp. strain CBS3. In this reaction, 4-CBA-CoA thioester synthesis is coupled to ATP cleavage. The studies described in this paper examine the intermediacy of 4-chlorobenzoyl-adenosine 5'phosphate diester (4-CBA-AMP) in the ligase reaction. The 4-CBA-AMP adduct was isolated from the ligase reaction mixture generated from magnesium adenosine 5-triphosphate (MgATP) and 4-CBA in the absence of CoA. The structure of the 4-CBA-AMP was verified by 1H- 13C-, and 31P-nuclear magnetic resonance analysis. Single-turnover reactions carried out with 14C-labeled 4-CBA in a rapid quench apparatus demonstrated formation of the enzyme. 4-CBA-AMP.MgPPi complex from the enzyme.4-CBA.MgATP complex at a rate of 135 s-1. The rate of ligand release from the enzyme.4-CBA-AMP.MgPPi complex was measured at 0.013 s-1. Single-turnover reactions of [14C]-4-CBA, MgATP, and CoA catalyzed by the ligase revealed that the 4-CBA-AMP intermediate formed reaches a maximum level of 25% of the starting 4-CBA within 10 ms and then declines with the formation of the 4-CBA-CoA. The rates of the adenylation and thioesterification partial reactions, determined by kinetic simulation of the rate data, are nearly equal (135 and 100 s-1). Substitution of CoA with the slow substrate pantetheine did not significantly alter the rate of the adenylation step but did reduce the rate of the thioesterification step to 2 s-1. The maximum level of 4-CBA-AMP reached during the single-turnover reaction of 4-CBA, MgATP, and pantetheine corresponded to one-half of the starting 4-CBA.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/4-chlorobenzoic acid,
http://linkedlifedata.com/resource/pubmed/chemical/4-halobenzoate-CoA ligase,
http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Monophosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Triphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Chlorobenzoates,
http://linkedlifedata.com/resource/pubmed/chemical/Coenzyme A Ligases,
http://linkedlifedata.com/resource/pubmed/chemical/Diphosphates,
http://linkedlifedata.com/resource/pubmed/chemical/Pantetheine
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pubmed:status |
MEDLINE
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pubmed:month |
Oct
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pubmed:issn |
0006-2960
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
15
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pubmed:volume |
35
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
13478-84
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:8873617-Adenosine Monophosphate,
pubmed-meshheading:8873617-Adenosine Triphosphate,
pubmed-meshheading:8873617-Catalysis,
pubmed-meshheading:8873617-Chlorobenzoates,
pubmed-meshheading:8873617-Coenzyme A Ligases,
pubmed-meshheading:8873617-Diphosphates,
pubmed-meshheading:8873617-Kinetics,
pubmed-meshheading:8873617-Models, Chemical,
pubmed-meshheading:8873617-Pantetheine,
pubmed-meshheading:8873617-Pseudomonas
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pubmed:year |
1996
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pubmed:articleTitle |
Determination of the chemical pathway for 4-chlorobenzoate:coenzyme A ligase catalysis.
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pubmed:affiliation |
Department of Chemistry and Biochemistry, University of Maryland, College Park 20742, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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