Abstract
The polyphosphate kinase oÍ Oscillatoria redekei grown in batch culture at constant
pH was investigated. The enzymes action required the presence of Mg2+, but was independent
of K+, Na+, PO4(3-) and even polyphosphate. The reaction was inhibited by (NH4)2SO4 and
competetively inhibited by ADP. In contrast to other organisms thus far analysed the polyphosphate kinase of O. redekei was an allosteric enzyme. ATP is the probable allosteric
activator. By this economical principle of regulation O. redekei is adapted optimally to
short-time oscillations of phosphate in the lake.
