The blue dye is a small molecule that runs faster than the proteins. Usually, you stop electrophoresis when the "dye front" reaches the bottom of the gel. Other things in the sample may also run ahead of the proteins, such as detergents and lipids. These can interfere with the sharpness of the dye front, but don't affect the protein bands, unless the amount is excessive.

Hi dear Paola Zanfardino

The Bromophenol blue is a dye that attached to protein to aware us where protein will stand after electrophoresis run.

Every protein has its charge, when you run a sample in the gel electrophoresis, the dye will seperated with attached protein, so you know where your protein stand and how many kilo-dalton it is.

Every row(marker) in the gel indicate specific weight. the highest weight protein will stand finally.

So, i think the sample preparation need to be modified:

-Try with denaturation at 100 for 5min

Best regards!

Gels are generally dense webs that retain your samples basing on their size. The dye molecule is much lighter and smaller than any protein (including your protein marker) and thats why excess dye migrates faster and originates those bands.

The blue dye is a small molecule that runs faster than the proteins. Usually, you stop electrophoresis when the "dye front" reaches the bottom of the gel. Other things in the sample may also run ahead of the proteins, such as detergents and lipids. These can interfere with the sharpness of the dye front, but don't affect the protein bands, unless the amount is excessive.