Fluorometric Detection of Inositol Phosphates and the Activity of Their Enzymes with Synthetic Pores: Discrimination of IP7 and IP6 and Phytate Sensing in Complex Matrices

Abstract

We report the fluorometric and noninvasive detection of inositol phosphates, which act as privileged blockers of synthetic pores. Phytate (IP6) and IP7 recognition in the pore occurs substoichiometrically in the low nanomolar range, with more than 2 orders of magnitude higher sensitivity than the best available alternative. Zn2+-mediated fluorometric discrimination between IP6 and IP7 demonstrates that significant pore discrimination challenges can be solved with judiciously selected additives. The detectability of inositol phosphate enzyme activity was exemplified with phytase. Phytate sensing was accomplished in complex matrices such as extracts from almonds, soybeans, or lentils, using phytase as a specific signal generator. These results are important because they not only add essential evidence in support of the usefulness of synthetic pores as multianalyte sensors in complex matrices but also reveal the existence of privileged analytes that can provide access to submicromolar sensitivity without the...