Bio-Rad GS-900™ Calibrated Densitometer - Manual (Page 63)

Problem Cause Solution
Other Problems
Wavy spots Insufficient overlay solution used Overlay the gel with water-saturated
in gel casting butanol (n-butanol, l-butanol, or t-butanol)
or t-amyl alcohol immediately after gel
casting. These ensure that the gel has a
clean, straight top edge
Use precast gels
Use the overlay recommended by the
manufacturer of the electrophoresis cell
Localized wavy Problems with casting second- Optimize the APS and TEMED
disturbance of spots dimension acrylamide gel: concentrations
not evenly polymerized,
gel cassette leaking, etc. Degas solutions prior to the addition
of APS/TEMED
Perform casting at room temperature,
warming the glass plates if necessary.
Be aware that the polymerization process
is temperature dependent. If the
temperature is too low, polymerization
may be compromised
Use precast gels
Known proteins appearing Protein carbamylation Do not prepare samples too far ahead
as multiple spots or at the of time in urea
wrong position
Do not expose urea-containing samples to
high pH or temperatures that exceed 30°C
Protein oxidation Increase DTT concentration
Protein proteolysis Add protease inhibitors, perform
(during sample preparation) manipulations as quickly as possible,
and keep solutions as cold as possible
For further help or advice, please contact the Bio-Rad Technical Support department. In the United States, the Technical Support department
is open Monday–Friday, 5:00 AM–5:00 PM, Pacific time.
Phone: 1-800-424-6723
Fax: 1-510-741-5802
Email: [email protected] (for U.S. and international customers)
Online technical support and worldwide contact information are available at www.consult.bio-rad.com.
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2-D Electrophoresis Guide Troubleshooting