Abstract: The invention provides compounds, compositions, methods, substrates, and kits useful for analyzing the metabolic activity in cells, tissue, and animals and for screening test compounds for their effect on cytochrome P450 activity. In particular, a one-step and two-step methods using luminogenic molecules, e.g. luciferins or coelenterazines, that are cytochrome P450 substrates and that are also bioluminescent enzyme, e.g., luciferase, pro-substrates are provided. The present method further provides a method for stabilizing and prolonging the luminescent signal in a luciferase-based assay using luciferase stabilizing agents such as reversible luciferase inhibitors.

Abstract: A method to detect the presence or amount of at least one molecule in a sample which employs a derivative of luciferin or a derivative of a fluorophore is provided. Compounds and compositions for carrying out the methods of the invention are also provided.

Abstract: A mutant hydrolase optionally fused to a protein of interest is provided. The mutant hydrolase is capable of forming a bond with a substrate for the corresponding nonmutant (wild-type) hydrolase which is more stable than the bond formed between the wild-type hydrolase and the substrate and has at least two amino acid substitutions relative to the wild-type hydrolase. Substrates for hydrolases comprising one or more functional groups are also provided, as well as methods of using the mutant hydrolase and the substrates of the invention. Also provided is a fusion protein capable of forming a stable bond with a substrate and cells which express the fusion protein.

Abstract: The present invention relates to single and dual reporter luminescence assays utilizing reagents to quench an optical, e.g., an enzyme-mediated luminescence, reaction. In one embodiment of the invention, a reagent is added to an assay which selectively quenches a first enzyme-mediated luminescence reaction without affecting a subsequent distinct enzyme-mediated luminescent reaction(s). An assay kit containing one or more selective quench reagents, and compositions comprising the quench reagent(s), are also provided.

Abstract: A mutant hydrolase optionally fused to a protein of interest is provided. The mutant hydrolase is capable of forming a bond with a substrate for the corresponding nonmutant (wild-type) hydrolase which is more stable than the bond formed between the wild-type hydrolase and the substrate and has at least two amino acid substitutions relative to the wild-type hydrolase. Substrates for hydrolases comprising one or more functional groups are also provided, as well as methods of using the mutant hydrolase and the substrates of the invention. Also provided is a fusion protein capable of forming a stable bond with a substrate and cells which express the fusion protein.

Abstract: A sensitive bioluminescent assay to detect proteases, including caspases and proteases that specifically cleave a peptide substrate having aspartate, is provided. In one embodiment, the assay employs an aminoluciferin or a carboxy-terminal protected derivative thereof covalently linked via a peptide bond to a substrate for a caspase or an aminoluciferin or a carboxy-terminal protected derivative thereof covalently linked via a peptide bond to a peptide substrate comprising aspartate that is specifically cleaved by a protease specific for the substrate.

Abstract: The invention encompasses kits for an improved method for measuring membrane potential using compounds of the formula I as potentiometric probes. These probes may be used in combination with other fluorescent indicators such as Indo-1, Fura-2, and Fluo-3, such probes may be used in microplate reading devices such as FLIPR™, fluorescent imaging plate reader, sold by Molecular Devices Corp., of Sunnyvale, Calif.; flow cytometers; and fluorometers. Such probes are used to measure membrane potential in live cells wherein X is O or S; and n is 1 or 2.

Abstract: A method of measuring the enzymatic activity of a luciferase includes contacting a luminogenic protein, such as a luciferase, with a protected luminophore to form a composition; and detecting light produced from the composition. The protected luminophore provides increased stability and improved signal-to-background ratios relative to the corresponding unmodified coelenterazine.

Abstract: A mutant hydrolase optionally fused to a protein of interest is provided. The mutant hydrolase is capable of forming a bond with a substrate for the corresponding nonmutant (wild-type) hydrolase which is more stable than the bond formed between the wild-type hydrolase and the substrate. Substrates for hydrolases comprising one or more functional groups are also provided, as well as methods of using the mutant hydrolase and the substrates of the invention. Also provided is a fusion protein capable of forming a stable bond with a substrate and cells which express the fusion protein.

Abstract: A method of measuring the enzymatic activity of a luciferase includes contacting a luminogenic protein, such as a luciferase, with a protected luminophore to form a composition; and detecting light produced from the composition. The protected luminophore provides increased stability and improved signal-to-background ratios relative to the corresponding unmodified coelenterazine.

Abstract: A mutant hydrolase optionally fused to a protein of interest is provided. The mutant hydrolase is capable of forming a bond with a substrate for the corresponding nonmutant (wild-type) hydrolase which is more stable than the bond formed between the wild-type hydrolase and the substrate. Substrates for hydrolases comprising one or more functional groups are also provided, as well as methods of using the mutant hydrolase and the substrates of the invention. Also provided is a fusion protein capable of forming a stable bond with a substrate and cells which express the fusion protein.

Abstract: A mutant hydrolase optionally fused to a protein of interest is provided. The mutant hydrolase is capable of forming a bond with a substrate for the corresponding nonmutant (wild-type) hydrolase which is more stable than the bond formed between the wild-type hydrolase and the substrate and has at least two amino acid substitutions relative to the wild-type hydrolase. Substrates for hydrolases comprising one or more functional groups are also provided, as well as methods of using the mutant hydrolase and the substrates of the invention. Also provided is a fusion protein capable of forming a stable bond with a substrate and cells which express the fusion protein.

Abstract: A method to detect the presence or amount of at least one molecule in a sample which employs a derivative of luciferin or a derivative of a fluorophore is provided.

Abstract: A sensitive bioluminescent assay to detect proteases including caspases, trypsin and tryptase is provided.

Abstract: A sensitive bioluminescent assay to detect proteases including caspases, trypsin and tryptase is provided.

Abstract: A sensitive bioluminescent assay to detect proteases including caspases, trypsin and tryptase is provided.

Abstract: A mutant hydrolase optionally fused to a protein of interest is provided. The mutant hydrolase is capable of forming a bond with a substrate for the corresponding nonmutant (wild-type) hydrolase which is more stable than the bond formed between the wild-type hydrolase and the substrate and has at least two amino acid substitutions relative to the wild-type hydrolase. Substrates for hydrolases comprising one or more functional groups are also provided, as well as methods of using the mutant hydrolase and the substrates of the invention. Also provided is a fusion protein capable of forming a stable bond with a substrate and cells which express the fusion protein.

Abstract: A mutant hydrolase optionally fused to a protein of interest is provided. The mutant hydrolase is capable of forming a bond with a substrate for the corresponding nonmutant (wild-type) hydrolase which is more stable than the bond formed between the wild-type hydrolase and the substrate and has at least two amino acid substitutions relative to the wild-type hydrolase. Substrates for hydrolases comprising one or more functional groups are also provided, as well as methods of using the mutant hydrolase and the substrates of the invention. Also provided is a fusion protein capable of forming a stable bond with a substrate and cells which express the fusion protein.

Abstract: The invention encompasses kits for an improved method for measuring membrane potential using compounds of the formula I as potentiometric probes. These probes may be used in combination with other fluorescent indicators such as Indo-1, Fura-2, and Fluo-3, such probes may be used in microplate reading devices such as FLIPR™, fluorescent imaging plate reader, sold by Molecular Devices Corp., of Sunnyvale, Calif.; flow cytometers; and fluorometers. Such probes are used to measure membrane potential in live cells.

Abstract: The invention encompasses an improved method for measuring membrane potential using compounds of the formula I as potentiometric probes. These probes may be used in combination with other fluorescent indicators such as Indo-1, Fura-2, and Fluo-3, such probes may be used in microplate reading devices such as FLIPR™, fluorescent imaging plate reader, sold by Molecular Device Corp., of Sunnyvale, Calif.; flow cytometers; and fluorometers.