For nitrocellulose or PVDF membrane following Western blot detection using a chemiluminescent or fluorescent substrate system: Following transfer, air dry the membrane and place in an envelope, preferably on top of a supported surface to keep the membrane flat. The blot can be stored indefinitely at -80 degrees C. When ready to reprobe, prewet the PVDF blot with alcohol for a few seconds, followed by a few rinses with pure water to reduce the alcohol concentration. Then proceed as normal with blocking step.
FOR STRIPPING/REPROBING OF MEMBRANES:
Harsh protocol (see NOTE below for modifications)
1) Submerge the membrane in stripping buffer (100 mM BME, 2% SDS, 62.5 mM Tris-HCl, pH 6.7) and incubate at 50 degrees C for 30 min with occasional agitation. If more stringent conditions necessary, incubate at 70 degrees C.
2) Wash 2 x 10 min in TBS-T/PBS-T at room temperature.
3) Block the membrane by immersing in 5% blocking reagent TBS-T or PBS-T for 1 hr at room temperature.
4) Immunodetection
NOTE: Often you don't need such harsh conditions to remove antibodies from their proteins. The stringency of one or several of the variables can be decreased: lower the temperature, decrease the time, less BME, less SDS, etc. An especially mild but still often effective stripping protocol is lower pH incubation. Example: pH 2.0 Tris 50-100 mM, 30-60 min incubation (you may do two incubations if you wish). Then rinse and block as usual. If you do not wish to re-use the membrane immediately after stripping, you can store the membrane in plastic wrap (wet, you do not want it to dry out). Another simple, mild stripping buffer is 0.1 M glycine•HCl (pH 2.5-3.0), incubation 30 min to 2 hrs room temperature or 37 degrees C, depending on the antibody.
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