Surface acoustic wave enzyme sensor applied to the kinetic assay of acid phosphatase

The acid phosphatase hydrolysis of phenylphosphoric acid (at pH 5 and at 25 degrees C) with a new type of liquid-immersion surface acoustic wave enzyme sensor (SAW) is described, A mathematical model was derived to estimate the kinetic parameters and to determine the concentrations of enzyme and substrate, The inhibition of the product to the enzyme activity was involved In the model. The Michaelis constant was estimated to be 1.17 x 10(-4) mol l(-1). The recovery of the sensor system was 97.4-104.4% (n = 6). The effects of temperature and pH on the enzyme activity were discussed. The proposed model compared favourably with the linear method which indicated that the model gave more precise results.