Abstract
Catalytic activity of two active sites of transketolase and their affinity towards the substrates (xylulose-5-phosphate and ribose-5-phosphate) has been studied in the presence of Ca2+ and Mg2+. In the presence of Ca2+, the active sites exhibit negative cooperativity in binding both xylulose-5-phosphate (donor substrate) and ribose-5-phosphate (acceptor substrate) and positive cooperativity in the catalytic transformation of the substrates. In the presence of Mg2+, nonequivalence of the active sites is not observed.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Catalytic Domain
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Kinetics
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Pentosephosphates / metabolism
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Ribosemonophosphates / metabolism
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Saccharomyces cerevisiae / chemistry
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae Proteins / chemistry*
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Saccharomyces cerevisiae Proteins / metabolism
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Substrate Specificity
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Transketolase / chemistry*
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Transketolase / metabolism
Substances
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Pentosephosphates
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Ribosemonophosphates
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Saccharomyces cerevisiae Proteins
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ribose-5-phosphate
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xylulose-5-phosphate
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Transketolase