Rev. Bras. Ciênc. Solo.1998;22(3):403-9.
Effect of base saturation on phosphatase activities from a coastal tableland soil cultivated with orange tree. II. Kinetic constants
01/Sep/1998
DOI: 10.1590/S0100-06831998000300005
The kinetic constants Kmapp and Vmaxapp of phosphatase activity from a coastal tableland soil grown with orange trees, submitted to different base saturation levels (32.0; 45.0; 64.0 and 76.6%), were determined. These determinations were made in optimum pH values for alkaline and acid phosphatases and in the pH values obtained for each base saturation level. Phosphatase activity has followed Michaelis-Menten kinetics, regardless the soil base saturation levels or pH values used for enzymatic activity evaluation. Increases in the soil bases saturation resulted in lower Kmapp values for both enzymes, while Vmaxapp was increased for alkaline phosphatase and did not show significant variation for acid phosphatase. Decreases in Kmapp and increases in Vmaxapp values in response to increasing soil bases saturation were also observed for phosphatases evaluated at pH values found at each soil base saturation level. The most remarkable changes in Kmapp and Vmaxapp in response to soil base saturation were the result of shifts in pH values.
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