Cooperative binding of substrates to transketolase from Saccharomyces cerevisiae
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- Sevostyanova, I.A., Selivanov, V.A., Yurshev, V.A. et al. Biochemistry Moscow (2009) 74: 789. doi:10.1134/S0006297909070128
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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.
Key wordstransketolase nonequivalence of active sites bivalent cations xylulose-5-phosphate ribose-5-phosphate