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non-specific band persistent at 29kDa - western blot non-specific bands (Jun/11/2009 )

hi all,

Our lab offlate has been having this problem. We work on frog skin proteins and irrespective of the antibody used, we always see two band at size 29kDa region.One being very thick and the other thin. These two bands always crop up alongwith the band that shows up in our region of interest.we are unable to solve this.The two bands are very prominent during Ponceau step too and perfectly show up irrespective of the protein antibody-moniclonal or polyclonal.
can any one give some suggestions?


If that ptn is recombinant, then it may b due to premature termination.
If the ptn is a native one (Probbly directly from frog) the bands may b due to mature and preprossed ptn


Are your primary antibodies conjugated, or do you use a secondary antibody to visualize them? If you use a secondary Ab, perhaps it's cross-reacting with the protein(s) in the aberrant bands.