アイテム詳細

要旨

Sediment phosphatases of a small first-order stream were investigated using 4-methylumbelliferyl phosphate. The degradation of organically bound phosphorus was inferred to involve an unidentified number of isozymes. Two pH-dependent isozyme groups could be identified, with activity optima occurring under acid (pH 5.0-6.0) and alkaline (pH 8.0-9.0) conditions. The multiphasic kinetic responses of the phosphatases varied markedly from sample to sample and were not correlated with the measured sediment substrate pools (organic matter, total phosphorus, soluble reactive phosphorus). The presence of multiple phosphatases implies that regulation of enzyme synthesis occurs in response to the competition for specific substrates.