Can you give more explanation about " I see it also on other people's ban on the internet"?

What's the concentration of ur primary antibody? What's your blocking solution?

Do u try diluting primary Ab in addition to increase blocking solution? Does the band also appear?

Thanks marwa. I checked images on internet where the same antibody was used. I saw the same picture as mine.

It's a one time primary antibody with HRP from abcam, no need for secondary antibody. I used 1 in 3000 dilution

I have not tried increasing blocking. 1 % milk. 1hr.

Thanks

Your primary antibody might be too high in concentration and could bind non-specifically to other unblocked proteins on the membrane. I would suggest you reduce the primary antibody concentration (to about 1:10,000 and if the two bands still appear, reduce further to 1:20,000) and, more importantly, block in 5% milk for 1 hr.

it may be an smaller isoform of alpha tubulin

Look here, it's not the same Ab

Look at lane 3, when he diluted the primary Ab concentration with increasing the blocking solution 5%.

And he observed only one band