US3655516A
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Urea assay process and composition
Assignee: University of Michigan-Ann Arbor
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Filing: 1969-10-10
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Granted: 1972-04-11
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Expires: 1989-10-10
Abstract
Abstract Assay of urea is provided by spectrophotometric measurement of a test solution containing the urea to be assayed together with ATP: urea amido-lyase and adenosine triphosphate as co-substrate for the enzyme, together with nicotine adenine dinucleotide, reduced; phosphoenol pyruvate; lactate dehydrogenase; pyruvate kinase; and magnesium and potassium ions. The transformation of the urea is followed quantitatively by optical absorption measurements at 340 millimicrons. The assay is unaffected by the presence of non-urea nitrogen, such as ammonia.
Inventors
- 👤 Robert J Roon
- 👤 Bruce Levenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:43
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/58
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
27 words
The method in accordance with claim 1 wherein said disappearance of said nicotine adenine dinucleotide is determined by optical absorption at a wavelength of about 340 millimicrons.
Claim 2
Dependent Claim
17 words
The method in accordance with claim 1 wherein said ATP: urea amido-lyase is derived from Candid utilis.
Claim 3
Dependent Claim
19 words
The method in accordance with claim 1 wherein said test solution is buffered to a pH of about 8.
Claim 4
Dependent Claim
71 words
The method in accordance with claim 4 wherein said test solution contains, per unit volume of about 3 ml, the following: tris(hydroxymethyl)aminomethane, 0.1 molar, pH 8: 2.5 ml. magnesium sulfate, 0.5 molar: 0.06 ml. potassium chloride, 2 molar: 0.12 ml. adenosine-5-triphosphate, Na2: 6.6 mg. nicotine adenine dinucleotide, reduced, 0.01 molar: 0.05 ml. phosphoenol pyruvate, 0.06 molar: 0.1 ml. lactate dehydrogenase: 5 I.U. pyruvate kinase: 5 I.U. ATP: urea amido-lyase: 0.2 mg.
Claim 5
Dependent Claim
33 words
A composition of matter adapted for urea assay consisting essentially of a mixture of ATP: urea amido-lyase; adenosine-5-triphosphate; nicotine adenine dinucleotide, reduced; phosphoenol pyruvate; lactate dehydrogenase; pyruvate kinase; divalent magnesium, and monovalent potassium.
Claim 6
Dependent Claim
54 words
A composition in accordance with claim 6 in which the components are present in the following relative proportions: ATP: urea amido-lyase: 0.2 grams adenosine-5-triphosphate, as disodium salt:6.6 grams nicotine adenine dinucleotide, reduced: 0.5 millimols phosphoenol pyruvate: 6 millimols lactate dehydrogenase: 5000 I.U. pyruvate kinase: 5000 I.U. magnesium cation: 0.03 mols potassium cation: 0.24 mols
References Cited (Backward Citations)
US3527674A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-11 | 1975-10-11 | 1976-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-11 | 1979-10-11 | 1980-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-11 | 1983-10-11 | 1984-04-11 | $7700.00 | Window Closed / Lapsed |