Abstract
Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the discontinuous system of Laemmli is used world-wide for analytical and preparative gel electrophoresis of polypeptides. A minor but disturbing problem is the difficulty of concentrating highly diluted solutions and determining their protein content after 2-mercaptoethanol-SDS solubilization. We describe a solution to both of these problems, detailing a two-step procedure which takes advantage of the low solubility of potassium dodecyl sulfate (KDS). Removal of excess of SDS and 2-mercaptoethanol, and concentration of proteins from even a nanomolar solution, is achieved by a two-step KDS precipitation. Free dodecyl sulfate is precipitated in step one, while KDS proteins are pelleted in the second step, allowing the thiol agents to be discarded with the supernatant. The effects of changing [SDS] and[KCl], temperature, and pH were studied to optimize the separation of free SDS from proteins. After final precipitation, the hundred- or thousandfold concentrated proteins can be suspended in a small volume of any required medium. The procedure allows protein determination by the Lowry method, peptide mapping of 2-mercaptoethanol-SDS solubilized polypeptides, and all other analyses which are otherwise hampered by excesses of SDS and/or thiol reagents.
| Original language | English |
|---|---|
| Pages (from-to) | 34-39 |
| Number of pages | 6 |
| Journal | Analytical Biochemistry |
| Volume | 213 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 1993 |
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ASJC Scopus subject areas
- Biochemistry
- Biophysics
- Molecular Biology
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Selective removal of free dodecyl sulfate from 2-mercaptoethanol-SDS-solubilized proteins before KDS-protein precipitation. / Sandri, M.; Rizzi, C.; Catani, C.; Carraro, U.
In: Analytical Biochemistry, Vol. 213, No. 1, 1993, p. 34-39.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Selective removal of free dodecyl sulfate from 2-mercaptoethanol-SDS-solubilized proteins before KDS-protein precipitation
AU - Sandri, M.
AU - Rizzi, C.
AU - Catani, C.
AU - Carraro, U.
PY - 1993
Y1 - 1993
N2 - Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the discontinuous system of Laemmli is used world-wide for analytical and preparative gel electrophoresis of polypeptides. A minor but disturbing problem is the difficulty of concentrating highly diluted solutions and determining their protein content after 2-mercaptoethanol-SDS solubilization. We describe a solution to both of these problems, detailing a two-step procedure which takes advantage of the low solubility of potassium dodecyl sulfate (KDS). Removal of excess of SDS and 2-mercaptoethanol, and concentration of proteins from even a nanomolar solution, is achieved by a two-step KDS precipitation. Free dodecyl sulfate is precipitated in step one, while KDS proteins are pelleted in the second step, allowing the thiol agents to be discarded with the supernatant. The effects of changing [SDS] and[KCl], temperature, and pH were studied to optimize the separation of free SDS from proteins. After final precipitation, the hundred- or thousandfold concentrated proteins can be suspended in a small volume of any required medium. The procedure allows protein determination by the Lowry method, peptide mapping of 2-mercaptoethanol-SDS solubilized polypeptides, and all other analyses which are otherwise hampered by excesses of SDS and/or thiol reagents.
AB - Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the discontinuous system of Laemmli is used world-wide for analytical and preparative gel electrophoresis of polypeptides. A minor but disturbing problem is the difficulty of concentrating highly diluted solutions and determining their protein content after 2-mercaptoethanol-SDS solubilization. We describe a solution to both of these problems, detailing a two-step procedure which takes advantage of the low solubility of potassium dodecyl sulfate (KDS). Removal of excess of SDS and 2-mercaptoethanol, and concentration of proteins from even a nanomolar solution, is achieved by a two-step KDS precipitation. Free dodecyl sulfate is precipitated in step one, while KDS proteins are pelleted in the second step, allowing the thiol agents to be discarded with the supernatant. The effects of changing [SDS] and[KCl], temperature, and pH were studied to optimize the separation of free SDS from proteins. After final precipitation, the hundred- or thousandfold concentrated proteins can be suspended in a small volume of any required medium. The procedure allows protein determination by the Lowry method, peptide mapping of 2-mercaptoethanol-SDS solubilized polypeptides, and all other analyses which are otherwise hampered by excesses of SDS and/or thiol reagents.
UR - http://www.scopus.com/inward/record.url?scp=0027166219&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027166219&partnerID=8YFLogxK
U2 - 10.1006/abio.1993.1382
DO - 10.1006/abio.1993.1382
M3 - Article
C2 - 8238879
AN - SCOPUS:0027166219
VL - 213
SP - 34
EP - 39
JO - Analytical Biochemistry
JF - Analytical Biochemistry
SN - 0003-2697
IS - 1
ER -