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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
1
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pubmed:dateCreated |
1993-11-12
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pubmed:abstractText |
Phenylalanine dehydrogenase from Thermoactinomyces intermedius and leucine dehydrogenase from Bacillus stearothermophilus show a 59% sequence similarity in their substrate-binding domains, although their substrate specificities are different. We prepared a phenylalanine dehydrogenase mutant enzyme whose inherent hexapeptide segment (124F-V-H-A-A-129R) in the substrate-binding domain was replaced by the corresponding part of leucine dehydrogenase (M-D-I-I-Y-Q) in order to investigate the mechanism of substrate recognition by phenylalanine dehydrogenase. The catalytic efficiencies (kcat/Km) of the mutant enzyme with aliphatic amino acids and aliphatic keto acids as substrates were 0.5 to 2% of those of the wild-type enzyme. In contrast, the efficiencies for L-phenylalanine and phenylpyruvate decreased to 0.008 and 0.035% of those of the wild-type enzyme, respectively. These results suggest that the hexapeptide segment plays an important role in the substrate recognition by phenylalanine dehydrogenase.
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Jul
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pubmed:issn |
0021-924X
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
114
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
69-75
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pubmed:dateRevised |
2009-11-19
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pubmed:meshHeading |
pubmed-meshheading:8407879-Amino Acid Oxidoreductases,
pubmed-meshheading:8407879-Amino Acid Sequence,
pubmed-meshheading:8407879-Amino Acids,
pubmed-meshheading:8407879-Base Sequence,
pubmed-meshheading:8407879-Circular Dichroism,
pubmed-meshheading:8407879-Geobacillus stearothermophilus,
pubmed-meshheading:8407879-Hydrogen-Ion Concentration,
pubmed-meshheading:8407879-Immunoblotting,
pubmed-meshheading:8407879-Kinetics,
pubmed-meshheading:8407879-Leucine Dehydrogenase,
pubmed-meshheading:8407879-Micromonosporaceae,
pubmed-meshheading:8407879-Molecular Sequence Data,
pubmed-meshheading:8407879-Molecular Weight,
pubmed-meshheading:8407879-Mutagenesis, Site-Directed,
pubmed-meshheading:8407879-Mutation,
pubmed-meshheading:8407879-Phenylalanine,
pubmed-meshheading:8407879-Sequence Homology, Amino Acid,
pubmed-meshheading:8407879-Spectrometry, Fluorescence,
pubmed-meshheading:8407879-Substrate Specificity,
pubmed-meshheading:8407879-Temperature
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pubmed:year |
1993
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pubmed:articleTitle |
Site-directed mutagenesis of a hexapeptide segment involved in substrate recognition of phenylalanine dehydrogenase from Thermoactinomyces intermedius.
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pubmed:affiliation |
Laboratory of Microbial Biochemistry, Kyoto University.
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pubmed:publicationType |
Journal Article
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