Die Substratspezifität „anorganischer“ Poly- und Metaphosphatasen. I. Optimale Wirkungsbedingungen für den enzymatischen Abbau von Poly- und Metaphosphaten

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Abstract
Enzyme preparations were made from autolyzed brewer''s yeast; enzyme 1 was precipitated between 20 and 40% saturated ammonium sulfate and enzyme 2 between 40 and 70%. The substrates investigated were pyro-phosphate, tripolyphosphate, tetrapolyphosphate, Graham''s salt (chain length 27-30), trimetaphosphate, and tetrametaphosphate. The optimum pH for activity of various enzyme fractions towards various substrates was determined: the optimum was near pH 7 for pyrophosphate and the metaphosphates, and near 8 for the poly-phosphates. Mg was necessary for the reaction, the optimal concentration being at about 1 - 2 x 10"2 [image]. Substrate concentrations for maximum enzyme activity are furnished. Substrate inhibition at high concentration was noted in the case of pyrophosphate; this inhibition was minimal when the ratio of Mg : P2O7 was 1 or more.