Abstract
A non-characterized gene, previously proposed as the D-tagatose-3-epimerase gene from Rhodobacter sphaeroides, was cloned and expressed in Escherichia coli. Its molecular mass was estimated to be 64 kDa with two identical subunits. The enzyme specificity was highest with D-fructose and decreased for other substrates in the order: D-tagatose, D-psicose, D-ribulose, D-xylulose and D-sorbose. Its activity was maximal at pH 9 and 40 degrees C while being enhanced by Mn(2+). At pH 9 and 40 degrees C, 118 g D-psicose l(-1) was produced from 700 g D-fructose l(-1) after 3 h.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Carbohydrate Epimerases / chemistry
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Carbohydrate Epimerases / metabolism*
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Cloning, Molecular
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Enzyme Activators / pharmacology
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Enzyme Stability
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Escherichia coli / genetics
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Fructose / metabolism*
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Gene Expression
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Hydrogen-Ion Concentration
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Manganese / pharmacology
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Molecular Sequence Data
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Molecular Weight
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Rhodobacter sphaeroides / enzymology*
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Rhodobacter sphaeroides / genetics
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Sequence Alignment
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Substrate Specificity
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Temperature
Substances
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Enzyme Activators
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psicose
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Fructose
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Manganese
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Carbohydrate Epimerases