Die Substratspezifität „anorganischer“ Poly- und Metaphosphatasen. III. Papierchromatographische Untersuchungen beim enzymatischen Abbau von anorganischen Poly- und Metaphosphaten

Abstract

The previously unknown intermediate stages in the enzymatic degradation of different poly- and metaphosphates are established by means of paper chromatography. Degradation schemes for the individual substrates are given. The degradation of high polymer phosphate chains, as in Graham''s salt, proceeds via low polymer chains to orthophosphate. Tetrapolyphosphate is cleaved via tri-polyphosphate and pyrophosphate, and tripolyphosphate via pyrophosphate, to orthophosphate. The enzymatic hydrolysis of metaphosphates yields initially the corresponding chain com-pounds, while trimetaphosphate is cleaved to tripolyphosphate and tetrametaphosphate to tetrapolyphosphate, which are further degraded as described to orthophosphate. A new classification of the inorganic phosphatases is effected on the basis of the reactions specifically catalyzed by the individual enzymes. The enzymes involved in the cleavage of polyphosphate chains with a degree of condensation up to 10 are termed oligophosphatases and are contrasted with the polyphosphate depolymerases and metaphosphatases (cyclophosphatases).