Abstract: Binding of inorganic phosphate to a phosphate binding protein can result in changes to the stacking of appropriately positioned chromophores, thereby resulting in a detectable change. The invention provides a phosphate-binding protein that undergoes a conformational change from an initial conformation to a final conformation upon binding of phosphate, wherein the protein carries a first label and a second label, and wherein the first and second labels are arranged such that they exhibit molecular stacking that is perturbed on changing from one conformation to the other. Preferred labels are rhodamines.

Abstract: Binding of inorganic phosphate to a phosphate binding protein can result in changes to the stacking of appropriately positioned chromophores, thereby resulting in a detectable change. The invention provides a phosphate-binding protein that undergoes a conformational change from an initial conformation to a final conformation upon binding of phosphate, wherein the protein carries a first label and a second label, and wherein the first and second labels are arranged such that they exhibit molecular stacking that is perturbed on changing from one conformation to the other. Preferred labels are rhodamines.

Abstract: Nucleoside diphosphates (NDPs) are detected or measured by following the dephosphorylation of the phosphoenzyme form of nucleoside diphosphate kinase (NDPK), and nucleoside triphosphates (NTPs) are detected or measured by following the phosphorylation of NDPK to its phosphoenozyme form. A typical process involves (a) causing NDP in sample to bind to NDPK phosphoenzyme, or causing NTP in sample to phosphorylate NDPK and (b) detecting a change in a characteristic of the enzyme which differs between its phosphorylated and unphosphorylated forms. This may be aided by labelling the enzyme. Quantitative data can be obtained. Both in vivo and in vitro measurements can be made.

Abstract: Nucleoside diphosphates (NDPs) are detected or measured by following the dephosphorylation of the phosphoenzyme form of nucleoside diphosphate kinase (NDPK), and nucleoside triphosphates (NTPs) are detected or measured by following the phosphorylation of NDPK to its phosphoenozyme form. A typical process involves (a) causing NDP in sample to bind to NDPK phosphoenzyme, or causing NTP in sample to phosphorylate NDPK and (b) detecting a change in a charateristic of the enzyme which differs between its phosphorylated and unphosphorylated forms. This may, be aided by labelling the enzyme. Quantitative data can be obtained. Both in vivo and in vitro measurements can be made.

Abstract: Nucleoside diphosphates (NDPs) are detected or measured by following the dephosphorylation of the phosphoenzyme form of nucleoside diphosphate kinase (NDPK), and nucleoside triphosphates (NTPs) are detected or measured by following the phosphorylation of NDPK to its phosphoenzyme form. A typical process involves (a) causing NDP in sample to bind to NDPK phosphoenzyme, or causing NTP in sample to phosphorylate NDPK and (b) detecting a change in a characteristic of the enzyme which differs between its phosphorylated and unphosphorylated forms. This may be aided by labelling the enzyme. Quantitative data can be obtained. Both in vivo and in vitro measurements can be made.

Abstract: Disclosed is a method for measuring or detecting inorganic phosphate ion in a sample. In the method, a sample is reacted with a phosphate-binding protein containing (i) an inorganic phosphate ion binding site and (ii) a detectable label that produces a signal whose amplitude changes detectably upon the binding of inorganic phosphate ion to the binding site, under conditions effective to allow binding of phosphate in the sample to the binding site. From a change in signal, the level of inorganic phosphate ion is measured or detected. Also disclosed are phosphate binding proteins for use in the method.