No abstract

While enzymes canonically operate in aqueous environments, several have been shown to also function in non‐aqueous solvents and/or solvent mixes. Phosphatases, for example, have been previously shown to hydrolyze phosphates in mixtures containing modest amounts of certain organic solvents. Here, detecting the fluorescent dephosphorylation product naphthol AS‐MX with fluorescence spectroscopy (ex: 388 nm, em: 512 nm) has shown commercial wheat germ acid phosphatase to be active in high amounts (up to ~70% by volume) of 1,4‐dioxane, 1,2‐ dimethoxyethane, 2‐methoxyethanol, dimethyl sulfoxide, and acetonitrile when the aqueous component was comprised of Tris buffer (pH 7). These solvent mixtures were also physically characterized to better understand differences in both relative naphthol AS‐MX fluorescence and wheat germ acid phosphatase activity across the different solvent mixtures investigated. These results suggest that phosphatase activity can be detected with less water that previously published. Support or Funding Information Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund and to the National Science Foundation’s Research Experience for Undergraduates program for partial support of this research.

Numerous enzymes have been demonstrated to be active in non-aqueous solutions, yet the utility of phosphatases under such conditions has been difficult to determine. Here, we demonstrate the ability to fluorescently detect naphthol AS-MX in high percentages 1,4-dioxane with a fluorescence differential compared with naphthol AS-MX phosphate. While intensities and maximum fluorescence wavelengths changed depending on solvent conditions, these results demonstrate this system's potential for testing phosphatase activity in high amounts of dioxane.