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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
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pubmed:dateCreated |
1995-11-14
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pubmed:abstractText |
The electron distribution in the coenzyme-substrate adduct of aspartate aminotransferase was changed by replacing active-site Arg386 with alanine and introducing a new arginine residue nearby. [Y225R, R386A]Aspartate aminotransferase decarboxylates L-aspartate to L-alanine (kcat = 0.04 s-1), while its transaminase activity towards dicarboxylic amino acids is decreased by three orders of magnitude (kcat = 0.19 s-1). Molecular-dynamics simulations based on the crystal structure of the mutant enzyme suggest that a new hydrogen bond to the imine N atom of the pyridoxal-5'-phosphate- aspartate adduct and an altered electrostatic potential around its beta-carboxylate group underlie the 650,000-fold increase in the ratio of beta-decarboxylase/transaminase activity.
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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 |
Sep
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pubmed:issn |
0014-2956
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
1
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pubmed:volume |
232
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
686-90
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pubmed:dateRevised |
2007-7-23
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pubmed:meshHeading |
pubmed-meshheading:7556224-Aspartate Aminotransferases,
pubmed-meshheading:7556224-Binding Sites,
pubmed-meshheading:7556224-Carboxy-Lyases,
pubmed-meshheading:7556224-Crystallography, X-Ray,
pubmed-meshheading:7556224-Electrochemistry,
pubmed-meshheading:7556224-Escherichia coli,
pubmed-meshheading:7556224-Hydrogen Bonding,
pubmed-meshheading:7556224-Kinetics,
pubmed-meshheading:7556224-Models, Molecular,
pubmed-meshheading:7556224-Mutagenesis, Site-Directed,
pubmed-meshheading:7556224-Pyridoxal Phosphate,
pubmed-meshheading:7556224-Substrate Specificity,
pubmed-meshheading:7556224-Thermodynamics
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pubmed:year |
1995
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pubmed:articleTitle |
Changing the reaction specificity of a pyridoxal-5'-phosphate-dependent enzyme.
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pubmed:affiliation |
Biochemisches Institut, Universität Zürich, Switzerland.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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