Color control system
First Claim
1. An assay system for colorimetric measurement and determination of NAD(P)H, NAD(P), or an enzyme substrate which reacts to form or consume NAD(P)H wherein the assay system comprises:
- a diaphorase which catalyzes NAD(P)H-dependent reduction of a chromogen to cause a visible color change,a chromogen which is an electron accepting substrate of the diaphorase, and which produces a color change upon reduction by NAD(P)H, anda non-chromogenic competing substrate of the diaphorase in an amount sufficient to increase the range of concentrations that can be measured by the color change of the chromogen when the competing substrate is irreversibly reduced by the diaphorase,wherein the change in color caused by reduction of the chromogen occurs in a ratio of less than one molecule of dye for each molecule of NAD(P)H produced and is indicative of the concentration to be determined.
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Abstract
An assay system useful for the determination of NAD(P)H, NAD(P), or a substrate of an enzyme which reacts with the formation or comsumption of NAD(P)H. Concentrations of organic substrates for example alcohol, cholesterol, uric acid, in a biological fluid such as saliva, blood or urine may be determined. The system includes a diaphorase which catalyzes a NAD(P)H-dependent reduction of a chromogen to cause a visible color change; this color change is indicative of the concentration sought to be determined. The system includes a chromogen which is a first substrate for the diaphorase which causes a color change when reduced by NAD(P)H, and a second substrate which is a competing substrate for the diaphorase; the competing substrate is irreversibly reduced by the diaphorase. The system is capable of measuring colorimetrically without dilution concentrations of organic compounds in biological fluids which previously could not be measured in such concentration. The system provides a convenient, practical sobriety test. The invention also provides a method for such determination and diagnostic kit.
39 Citations
61 Claims
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1. An assay system for colorimetric measurement and determination of NAD(P)H, NAD(P), or an enzyme substrate which reacts to form or consume NAD(P)H wherein the assay system comprises:
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a diaphorase which catalyzes NAD(P)H-dependent reduction of a chromogen to cause a visible color change, a chromogen which is an electron accepting substrate of the diaphorase, and which produces a color change upon reduction by NAD(P)H, and a non-chromogenic competing substrate of the diaphorase in an amount sufficient to increase the range of concentrations that can be measured by the color change of the chromogen when the competing substrate is irreversibly reduced by the diaphorase, wherein the change in color caused by reduction of the chromogen occurs in a ratio of less than one molecule of dye for each molecule of NAD(P)H produced and is indicative of the concentration to be determined. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A method for colorimetric measurement of the amount of an organic analyte in a sample wherein the method comprises:
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(a) oxidizing the organic analyte in the presence of NAD(P) and an NAD(P)-dependent dehydrogenase to produce NAD(P)H in an amount proportional to the amount of organic analyte, (b) irreversibly reducing a chromogen which is an electron accepting substrate of diaphorase in the presence of diaphorase and the NAD(P)H produced in (a) causing a measurable color change, (c) and irreversibly reducing a non-chromogenic competing substrate of diaphorase in the presence of diaphorase and the NAD(P)H produced in (a), wherein the competing substrate is present in an amount sufficient to expand the range of concentrations that can be measured by the color change of the chromogen, (d) wherein the color change produced upon reduction of the chromogen is in a ratio of less than one molecule of dye per molecule of NAD(P)H, and (e) measuring the color change caused by the chromogen, thereby determining the amount of analyte in the solution. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45, 46)
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47. A diagnostic device for the quantitative or qualitative determination of an organic analyte in a biological medium, which comprises:
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in combination, support means for a dehydrogenase capable of oxidizing the organic analyte, NAD(P), a chromogen which produces a color change upon reduction by NAD(P)H in the presence of diaphorase, a non-chromogenic competing substrate which is irreversibly reducible by NAD(P)H in the presence of diaphorase, and diaphorase, wherein the color change produced upon reduction of the chromogen occurs in a ratio of less than one molecule of dye per molecule of NAD(P)H. - View Dependent Claims (48, 49, 50)
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- 51. A test kit for colorimetric measurement of the amount of an organic analyte is solution wherein the analyte is capable of being oxidized in a NAD(P)-dependent dehydrogenase reaction to produce NAD(P)H, wherein the test kit comprises at least one reaction area means, containing NAD(P), a dehydrogenase capable of oxidizing the organic analyte, diaphorase, a chromogen which produces a color change upon irreversible reduction by NAD(P)H in the presence of diaphorase and a non-chromogenic competing substrate which is irreversibly reduced by NAD(P)H in the presence of diaphorase, wherein the amount of color produced upon reduction of the chromogen is less than that produced in the absence of the competing substrate and the color change occurs in a ratio of less than one molecule of dye per molecule of NAD(P)H produced, said color change being indicative of the concentration of the analyte to be determined.
Specification