Abstract
We found a new reaction of aspartic acid dehydrogenation, catalyzed by NADP(+)-dependent aspartate dehydrogenase, in vitamin B12-producing Klebsiella pneumoniae IFO 13541. The enzyme, which was purified from a crude extract of K.pneumoniae IFO 13541, catalyzes the oxidative deamination of aspartic acid to form oxaloacetic acid. This enzyme had a molecular mass of about 124 kDa consisting of two identical subunits. L-Aspartic acid was a substrate, although D-aspartic acid and L-glutamic acid were inactive. The enzyme showed maximal activity at about pH 7.0-8.0 for the oxidative deamination of L-aspartic acid, and it required NADP+ as a coenzyme, while NAD+ was inactive.
MeSH terms
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Amino Acid Oxidoreductases / isolation & purification*
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Amino Acid Oxidoreductases / metabolism
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Ammonia / analysis
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Ammonium Sulfate / chemistry
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Aspartic Acid / analysis
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Aspartic Acid / metabolism*
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Chromatography, Agarose
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Chromatography, DEAE-Cellulose
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Chromatography, High Pressure Liquid
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Electrophoresis, Polyacrylamide Gel
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Hot Temperature
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Hydrogen-Ion Concentration
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Klebsiella pneumoniae / enzymology
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Klebsiella pneumoniae / metabolism*
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Molecular Weight
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NADP / metabolism
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Oxaloacetates / analysis
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Protamines / chemistry
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Vitamin B 12 / biosynthesis*
Substances
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Oxaloacetates
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Protamines
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Aspartic Acid
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NADP
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Ammonia
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Amino Acid Oxidoreductases
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aspartate dehydrogenase
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Vitamin B 12
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Ammonium Sulfate