[Synthesis and some properties of immobilized transketolase].

A covalent binding of transketolase to bromo-cyanogen-activated Sepharose 4B at the pH value of the maximum activity and stability of the enzyme equal to 7,6 has been carried out. It has been shown that upon immobilization the enzyme retains up to 50% of its specific activity. The stability of the immobilized transketolase increases, depending on the degree of template activation 5- to 9-fold at 4 degrees C and 5- --20-fold at 50 degrees C. The value of the activity pH-optimum remains almost unchanged. In the presence of Mg2+ the pH-dependence curve somewhat broadens towards higher alkalinity whereas in the presence of Ca2+ it becomes less steep as compared to enzyme solution. The apparent Michaelis constant for substrates (pentose phosphates mixture) does not differ from Km for a free enzyme.