There has been some recent discussion in this group about artifact bands
of 50-60kDa on SDS-PAGE gels. Several sources of such bands have been
identified by various individuals including contaminants in 2-ME, fungal
growth in reagents, cytokeratins from skin, and bad water. It may also
be possible that proteins could be leached from the powder on gloves as
the powder is contaminated enough of it to cause allergies. I traced
the problem I was having several years ago in two different labs to the
presence of serum proteins on the glassware in which reagents were stored
or prepared. Every lab I am familiar with uses 100 and 500 ml serum
bottles to store reagents including gel and HPLC reagents. Therefore, I
suspect that this may be a common source of contaminating bands. I
resolved the problem by sequestering a dedicated set of glassware for
protein work and acid-cleaning it. The problem has not re-occurred for
the past eight years I have been doing this. When I was using glassware
from a common kitchen, it was often autoclaved before washing. It is
possible that autoclaving resulted in baking of proteins onto the glass.
I could recover about 1 mg/liter of Folin reactive protein by just
filling such glassware with PBS. Since cleaning glass with acid, I have
not detected any artifact protein bands nor HPLC peaks (1 pg/peak
sensitivity.) If people having this problem acid clean their gel plates,
they should rinse them in KOH-saturated ethanol to prevent a dentate gel
interface. I hope that this information as well as the information
already posted by others is helpful to anyone having this rather annoying
problem with artifact bands. Several of you contacted me by email for
this information when I was having a problem posting the text of my
messages, so I assume the above problem is fairly common. G.
--
Gary H. Butler, Ph.D.
Coriell Institute for Medical Research
401 Haddon Ave.
Camden, NJ 08103
Tel: (609) 757-9716
Fax: (609) 964 0254 Attn: Butler
Email: butler at UMDNJ.edu
