Hi Heba,

In my experiment, I'll dilute protein marker and protein sample with the "same sample buffer" (contain denaturing agent or not) to the equal volume.

I think that the denature form of marker protein can reveal more accurate molecular weight during gel electrophoresis.

Good luck.

Weber

Hi, if the marker is recommended for SDS PAGE the formula must have reducing and denaturing agents, so you can load it in your gel directly. Always check datasheets to be sure.

Good luck!

U should not denature ur marker, it is ready for use, not additional steps are required, so u just need to load the required volume (2-10ul) in ur gel.

Regarding ur sample,  u just need to added the volume of samples equivalent to the required ug, then added ur 2X sample buffer with ur reducing agent and denture it at 95C for 5 minutes.

Yes, It is true that markers used in western are ready to use. 

Only your samples are to prepare and add mercapthoethanol which is toxic and worse smell. Be careful handling it. 

Marker is pre-denatured, so you can use is directly. But we always dilute it with loading buffer to the same volume compared with samples, before we load it to the gel. It makes the lane more beautiful.

good luck!

You don't need to add denaturing agent to your pre-stained protein marker, you just need to add it to your samples with Laemmli sample buffer. I nornally