They are the same protein. The official designation now is ABCB1.

P-glycoprotein is highly glycosylated, which is why it runs as a broad band. In my experience, it actually ran as two broad bands, both with higher molecular weight than predicted by the amino acid sequence, centered at roughly 170 and 220 Da, I think. If you treat the protein with PNGase F, you can remove the carbohydrate to get a sharper band at the predicted molecular weight.

The low molecular weight band you are seeing is probably a proteolytic fragment. The linker region between the two tandem repeat domains is proteolytically sensitive.

There is lab lore to the effect that boiling the P-glycoprotein-containing samples in SDS-PAGE buffer causes the protein to disappear, so don't boil, or try both boiling and not boiling to see what happens.

Thank you Adam B Shapiro for guidance.

I got band above 250. I will follow your suggestion and try without boiling.

P-GP is the protein (often the functional form, modified etc.; see above), whereas MDR-1 is the gene name often used synonymously.

Andreas Eisenreich Thank you

Adam B Shapiro

Hi Sir,

I have tried to do western blotting (for ABCB1 PROTEIN) with and without heating protein and still i got so many bands NOT the single of the desired molecular weight.

What you will suggest me?

Thank you

Have you tried pre-treating the sample (prior to addition of SDS-PAGE sample buffer) with PNGase F to deglycosylate? Have you included protease inhibitor cocktail in the cell lysis buffer?

No i didn't pre treated the sample with protease inhibitor, i just tried by heating and without heating the sample and got same results in both cases.

Can you please share protocol to treate samples with protease inhibitors?

Thank you