Abstract: A method of preparing an enzyme-labeled ligand for use in specific binding assays for determining said ligand or a specific binding partner thereof, by covalently coupling said ligand or a binding analog thereof to an organic prosthetic group and combining the resulting coupled product with an apoenzyme to form a conjugated enzyme complex with said prosthetic group in said coupled product. Preferably, the conjugated enzyme complex in the resulting labeled conjugate exhibits holoenzyme activity which is affected by binding of said labeled conjugate by a specific binding partner of said ligand. Preferred prosthetic groups are flavin mononucleotide, heme, and, especially, flavin adenine dinucleotide, with preferred apoenzymes being apoperoxidase and, especially, apoglucose oxidase.

Abstract: A specific binding assay for determining a ligand in a liquid medium employing an organic prosthetic group residue, such as a residue of flavin adenine dinucleotide, flavin mononucleotide, or heme, as a label component in the labeled conjugate. Preferably, the label component is the prosthetic group residue alone or is a holoenzyme residue comprising such prosthetic group residue combined with an apoenzyme in the form of a holoenzyme complex. In the former case, the label component preferably is monitored in the assay by adding an apoenzyme after the binding reaction has been initiated and measuring the resultant holoenzyme activity. In the latter case, the label component is monitored simply by measuring holoenzyme activity. The assay method may follow conventional homogeneous and heterogeneous schemes. Preferred apoenzymes for use in the assay are apoglucose oxidase and apoperoxidase. The assay offers the advantages of colorimetric read-out and of being readily adaptable to automated techniques.

Abstract: A specific binding assay for determining a ligand in a liquid medium employing an organic prosthetic group residue, such as a residue of flavin adenine dinucleotide, flavin mononucleotide, or heme, as a label component in the labeled conjugate. Preferably, the label component is the prosthetic group residue alone or is a holoenzyme residue comprising such prosthetic group residue combined with an apoenzyme in the form of a holoenzyme complex. In the former case, the label component preferably is monitored in the assay by adding an apoenzyme after the binding reaction has been initiated and measuring the resultant holoenzyme activity. In the latter case, the label component is monitored simply by measuring holoenzyme activity. The assay method may follow conventional homogeneous and heterogeneous schemes. Preferred apoenzymes for use in the assay are apoglucose oxidase and apoperoxidase. The assay offers the advantages of colorimetric read-out and of being readily adaptable to automated techniques.

Abstract: A specific binding assay for determining a ligand in a liquid medium employing an organic prosthetic group residue, such as a residue of flavin adenine dinucleotide, flavin mononucleotide, or heme, as a label component in the labeled conjugate. Preferably, the label component is the prosthetic group residue alone or is a holoenzyme residue comprising such prosthetic group residue combined with an apoenzyme in the form of a holoenzyme complex. In the former case, the label component preferably is monitored in the assay by adding an apoenzyme after the binding reaction has been initiated and measuring the resultant holoenzyme activity. In the latter case, the label component is monitored simply by measuring holoenzyme activity. The assay method may follow conventional homogeneous and heterogeneous schemes. Preferred apoenzymes for use in the assay are apoglucose oxidase and apoperoxidase. The assay offers the advantages of colorimetric read-out and of being readily adaptable to automated techniques.

Abstract: A specific binding assay for determining a ligand in a liquid medium employing an organic prosthetic group residue, such as a residue of flavin adenine dinucleotide, flavin mononucleotide, or heme, as a label component in the labeled conjugate. Preferably, the label component is the prosthetic group residue alone or is a holoenzyme residue comprising such prosthetic group residue combined with an apoenzyme in the form of a holoenzyme complex. In the former case, the label component preferably is monitored in the assay by adding an apoenzyme after the binding reaction has been initiated and measuring the resultant holoenzyme activity. In the latter case, the label component is monitored simply by measuring holoenzyme activity. The assay method may follow conventional homogeneous and heterogeneous schemes. Preferred apoenzymes for use in the assay are apoglucose oxidase and apoperoxidase. The assay offers the advantages of colorimetric read-out and of being readily adaptable to automated techniques.