Investigating the kinetics of paramagnetic-beads linked alkaline phosphatase enzyme through microchannel resistance measurement in dielectric microchip

Real time monitoring of electrolyte resistance changes during hydrolysis of 4-nitrophenylphosphate (pNPP) by alkaline phosphatase (ALP) bound on paramagnetic-beads was performed into a small dielectric channel. The reaction kinetic fit with a non-competitive substrate-inhibition equation. Michaelis-Menten apparent constant, KMapp, was determined as 0.33±0.06 mM and the maximum apparent rate, Vmaxapp as 98±5 pM s−1. The detection limits were 15 fM for ALP and 0.75 mM for pNPP. This miniaturized device constitutes a powerful tool for analysis of interaction between ligands.