Patent US4086142A successfully refreshed from Google Patents.
US4086142A
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Decarboxylation of endogenous serum glutamate in transaminase assays
Assignee: Dow Chemical Co
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Filing: 1976-12-06
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Granted: 1978-04-25
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Expires: 1996-12-06
Abstract
Abstract A spectrophotometric method for carrying out transaminase determinations of biological fluids wherein endogenous glutamate in a biological fluid is decarboxylated prior to transaminase determinations with bacterial glutamic acid decarboxylase.
Inventors
- 👤 Charles Y. Huang
- 👤 William S. Stavropoulos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:15
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/48; C12Q1/52; C12N; C12N9/00; C12N9/88
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
102 words
In a colorimetric method for the determination of glutamic transaminase activity in biological fluids having endogenous glutamate present wherein the transaminase activity is determined by an assay for the amount of glutamate generated by an amino acid and α-oxoglutarate in the presence of the glutamic transaminase by measuring the absorbance of a color reaction product the improvement which comprises incubating prior to glutamate assay the biological fluid with an effective glutamate decarboxylating amount of a microbial glutamic acid decarboxylase at a pH of from about 4 to about 5 for a time sufficient to decarboxylate the endogenous glutamate in the biological fluid.
Claim 2
Dependent Claim
102 words
In a colorimetric method for the determination of glutamic transaminase activity in biological fluids having endogenous glutamate present wherein the transaminase activity is determined by an assay for the amount of glutamate generated by an amino acid and α-oxoglutarate in the presence of the glutamic transaminase by measuring the absorbance of a color reaction product the improvement which comprises incubating prior to glutamate assay the biological fluid with an effective glutamate decarboxylating amount of a microbial glutamic acid decarboxylase at a pH of from about 4 to about 5 for a time sufficient to decarboxylate the endogenous glutamate in the biological fluid.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein the glutamic acid decarboxylase is inactive at neutral or alkaline pH.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein the microbial glutamic acid decarboxylase is obtained from Escherichia coli.
Claim 5
Dependent Claim
11 words
The method of claim 4 wherein the biological fluid is serum.
Claim 6
Dependent Claim
17 words
The method of claim 1 wherein the change in absorbance of light is measured on a colorimeter.
Claim 7
Dependent Claim
27 words
The method of claim 3 wherein the amount of microbial glutamic acid decarboxylase present is from 0.4 to 4 international units per 100 microliters of biological fluid.
References Cited (Backward Citations)
US4024021A
Cited
US3992158A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-04-24 | 1981-10-24 | 1982-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-24 | 1985-10-24 | 1986-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-24 | 1989-10-24 | 1990-04-25 | $7700.00 | Window Closed / Lapsed |