Fluorometric detection of inositol phosphates and the activity of their enzymes with synthetic pores: Discrimination of IP(7) and IP(6) and phytate sensing in complex matrices

• Published in: Journal of the American Chemical Society Vol. 130; no. 11; pp. 3270 - 3272
• Main Authors: Butterfield, Sara M., Tran, Duy-Hien, Zhang, Honglu, Prestwich, Glenn D., Matile, Stefan
• Format: Journal Article
• Language: English
• Published: WASHINGTON Amer Chemical Soc 19.03.2008
• Subjects: Chemistry; Chemistry, Multidisciplinary; Physical Sciences; Science & Technology; MEMBRANES; CRISIS; ASSAYS; ION CHANNELS
• ISSN: 0002-7863
• DOI: 10.1021/ja710186e

We report the fluorometric and noninvasive detection of inositol phosphates, which act as privileged blockers of synthetic pores. Phytate (IP(6)) and IP(7) recognition in the pore occurs substoichiometrically in the low nanomalar range, with more than 2 orders of magnitude higher sensitivity than the best available alternative. Zn(2+)-mediatedl fluorometric discrimination between IP6 and IP7 demonstrates that significant pore discrimination challenges can be solved with judiciously selected additives. The delectability 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 need of refined sensing strategies.