US4219337A
Expired / Lapsed
US
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Assay for proteins and polypeptides
Assignee: Medical College of Wisconsin
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Filing: 1978-04-27
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Granted: 1980-08-26
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Expires: 1998-04-27
Abstract
Abstract An assay for proteins or polypeptides in solution using a reagent of Coomassie Brilliant Blue G250 dye in perchloric or hydrochloric acid. Upon mixture of the acidic reagent with a protein sample, the dye couples with the protein and undergoes a color change, following which the absorbance of the mixture can be measured to provide a quantitative analysis for the protein in the sample; the same procedure may be used for sample solutions containing polypeptides. Proteins and polypeptides with molecular weights above about 2000-3000 may be assayed.
Inventors
- 👤 Sidney E. Grossberg
- 👤 Joseph J. Sedmak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:26
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/68; G01N33/6803; G01N33/6827; G01N33/6839
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
116 words
An assay for proteins or polypeptides in solution, comprising the steps of: (1) mixing a sample solution containing a protein or polypeptide with an acidic reagent solution comprising Coomassie Brilliant Blue G25 dye and perchloric acid or hydrochloric acid to produce a change of color of the dye, the volume of sample solution and the volume of acidic reagent solution each being such as to provide a perchloric acid concentration in the resultant mixture of about 1.3% to 1.75% (w/v) or a hydrochloric acid concentration in the resultant mixture of about 0.6% to 1.2% (w/v), and (2) observing the color of the resultant mixture to determine the concentration of protein or polypeptide in the sample solution.
Claim 2
Dependent Claim
116 words
An assay for proteins or polypeptides in solution, comprising the steps of: (1) mixing a sample solution containing a protein or polypeptide with an acidic reagent solution comprising Coomassie Brilliant Blue G25 dye and perchloric acid or hydrochloric acid to produce a change of color of the dye, the volume of sample solution and the volume of acidic reagent solution each being such as to provide a perchloric acid concentration in the resultant mixture of about 1.3% to 1.75% (w/v) or a hydrochloric acid concentration in the resultant mixture of about 0.6% to 1.2% (w/v), and (2) observing the color of the resultant mixture to determine the concentration of protein or polypeptide in the sample solution.
Claim 3
Dependent Claim
24 words
An assay according to claim 1, wherein: the acidic reagent solution contains about 0.01 to 0.10% of Coomassie Brilliant Blue G250 dye by weight.
Claim 4
Dependent Claim
123 words
An assay for proteins or polypeptides in solution, comprising the steps of: (1) saturating a paper element with an acidic solution comprising about 2.6% to 3.5% (w/v) perchloric acid or about 1.2% to 2.4% (w/v) hydrochloric acid; (2) placing the paper element saturated under step (1) into a sample solution containing a protein or polypeptide, and thereafter removing the paper element from the sample solution; (3) placing the paper element from step (2) into an acidic reagent solution comprising Coomassie Brilliant Blue G250 dye and about 2.6% to 3.5% (w/v) perchloric acid or about 1.2% to 2.4% (w/v) hydrochloric acid to produce a change of color of the dye; and (4) observing the color change produced on the paper element under step (3).
Claim 5
Dependent Claim
123 words
An assay for proteins or polypeptides in solution, comprising the steps of: (1) saturating a paper element with an acidic solution comprising about 2.6% to 3.5% (w/v) perchloric acid or about 1.2% to 2.4% (w/v) hydrochloric acid; (2) placing the paper element saturated under step (1) into a sample solution containing a protein or polypeptide, and thereafter removing the paper element from the sample solution; (3) placing the paper element from step (2) into an acidic reagent solution comprising Coomassie Brilliant Blue G250 dye and about 2.6% to 3.5% (w/v) perchloric acid or about 1.2% to 2.4% (w/v) hydrochloric acid to produce a change of color of the dye; and (4) observing the color change produced on the paper element under step (3).
Claim 6
Dependent Claim
32 words
The assay of claim 3 wherein: the Coomassie Brilliant Blue G250 dye is present in the acidic reagent solution of step (3) at a concentration of about 0.01 to 0.10% by weight.
Claim 7
Dependent Claim
40 words
An assay according to claim 1 or claim 2, wherein: approximately equal volumes of sample solution and an acidic reagent solution containing about 2.6% to 3.5% (w/v) perchloric acid or about 1.2% to 2.4% (w/v) hydrochloric acid are mixed together.
Claim 8
Dependent Claim
38 words
A microassay according to claim 1 or claim 2, wherein: approximately 0.5 ml of acidic reagent solution and from 1 to 50 μl of sample solution are mixed together. (d) Amend claims 7-9 to read as shown below.
References Cited (Backward Citations)
US2785057A
Cited
US3980437A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-08-26 | 1984-02-25 | 1984-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-26 | 1988-02-25 | 1988-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-26 | 1992-02-25 | 1992-08-26 | $7700.00 | Window Closed / Lapsed |