Although alkaline phosphatase (APase) fromEscherichia colicrystallizes as a symmetric dimer, it displays deviations from Michaelis–Menten kinetics, supported by a model describing a dimeric enzyme with unequal subunits [Orha-novic´ S., Pavela-Vrancˇicˇ M. and Flogel-Mrsˇic´ M. (1994) Acta. , 87–95]. The possibility, that the observed asymmetry could be attributed to negative cooperativity in Mg2+ binding, has been examined. The influence of the metal ion content on the catalytic properties of APase from E. colihas been examined by kinetic analyses. .
