Biology Stack Exchange
Biology Stack Exchange

Questions tagged [sds-page]

Questions pertaining to sodium dodecyl sulfate polyacrylamide gel electrophoresis, a technique used to separate proteins according to electrophoretic mobility

33 questions
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When running gels what is the difference between constant volts or constant amps?

In general, you want to be consistent with running your gels either at constant volts or constant amps. However, it is very clear that during the progression of both PAGE and agarose gels, the free parameter changes due to the change in resistance…
bobthejoe
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What is the purpose of using two layers of gel in SDS- PAGE?

I just made a SDS-PAGE with a top layer of stacking gel and a bottom layer of separating gel with different pH values of 0.5M Tris-HCl. The stacking was 6.8 and the separating gel was 8.8. What about this pH change makes the gels different? What…
Stacked
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Why does migration distance depend on log of molecular weight in SDS-PAGE?

I really want to know why in the result of SDS PAGE, log of molecular weight(MW) and migration distance (distance from the loading well) have a linear relationship. Why is it log(MW) instead of MW? Thank you!
Eiswein.Y
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What would cause proteins to get stuck in the stacking layer of a SDS-Page gel

Typically when proteins aggregate, they will get stuck at the top of the well. However, we're seeing some protein aggregate in the stacking layer even when we're treating the loading volume with DTT. One peculiar attribute of this experiment is that…
bobthejoe
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Can I image Coomassie and GFP in gels at the same time with a fluorescence scanner?

I'm working with a GFP-tagged protein and am routinely using a fluorescence imager (GE Typhoon) and a standard optical scanner to capture fluorescent and absorption images, respectively, of my SDS-PAGE gels. The Typhoon supports multiple channels,…
Nick T
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How do Proteins migrate in MES vs. MOPS

My gels look significantly different in MES (2-(N-morpholino)ethanesulfonic acid) and MOPS (3-(N-morpholino)propanesulfonic acid). That is to be expected. What I don't understand is why the simple presence of the counter-ion significantly changes…
bobthejoe
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Does GTP-γS (GTP gamma S) bind all GTP-binding proteins?

I've just read an article Rab10 GTPase regulates ER dynamics and morphology - Nature Cell Biology 15, 169–178 (2013) doi:10.1038/ncb2647. In this paper, to identify Rab proteins in ER, first they isolated ER vesicles. Then washed them to remove…
Armacino
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How do SDS-PAGE gels differ in a Bis-Tris system vs. a Tris-Glycine system?

Protein migrate differently in Bis-Tris and Tris-Glycine gels. I was curious about the actual reasons why. Do certain gel systems result in a tighter resolution than others?
bobthejoe
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What kind of "size" does SDS-PAGE separate by?

What is the exact property of the protein that affects migration of bands in SDS-PAGE; is it length, volume, or mass? For example, will GGGGGGGGGG (glycine 10-mer; mw <600) migrate more or less than WWWWW (tryptophan 5-mer; mw >900)?
oryza
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What is SDS PAGE gel polymerization time?

I am working on 20% SDS PAGE. I want to know optimum polymerization time for 20% resolving gel and 6% stacking gel. If I increase the time then would it affect the band pattern?
kt123
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Why my proteins are migrating like this on SDS-page?

I'm trying to make a SDS-page of total proteins extracted from algae but I'm encountering two problems. First, when I depose my proteins in the wells the sample goes down and then it starts to move up the sides of the well. Second the result of my…
Radioactivestar88
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Relative densitometry from SDS PAGE

I'd like to perform densitometry on a Coomassie stained SDS PAGE gel to compare a recombinant protein's expression levels under two conditions. I'm using BioRad's Image Lab software. My questions are about what estimates can be made, given that…
bravetang8
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Troubleshooting SDS-PAGE of trypsin-treated BSA

I am currently working on SDS-PAGE technique having 20% acrylamide concentration for hydrolyzed BSA protein. Here I attached a gel photo for trypsin hydrolyzed BSA. I don't know , is it a good result and how do I interpreted this result?
kt123
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Why is my DNA band bulging?

This is the only image my the TA was able to get for us. And, we're using it for our lab report. The image isn't even ours. It's another group's image that we're sharing. But I don't understand why in the first lane there seems to be some bulging/…
user61816
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Can denatured GFP show fluorescence?

GFP ( green fluorescent protein) can show green fluorescence. And its fluorescence is due to the tri peptide chromophore which is given in below I was wondering, can we observe fluorescence, if we denature it by boiling at 95 degree celsius? Say can…
Science123
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