Artefacts on SDS PA gels

[Malcolm Moos Jr.]

I'm not sure it's been published, but in a conversation I had with him 
on the subject, Carl Merrill himself confirmed the origin of these 
troublesome bands as human keratin, which can find its way into various 
SDS PAGE reagents, including mercaptoethanol. There are some published 
reports implicating the latter as the cause of this artifact, but I've 
tested this myself and cannot reproduce these data. We have completely 
eliminated this problem with meticulous technique, which includes 
wearing gloves whenever touching any substance or piece of apparatus 
involved in the electrophoresis (especially combs, sample buffer, 
running buffer, and components thereof).

mlamkin at acs.bu.edu (Mark Lamkin) wrote:
>A while back, some one asked for help in explaining the presence of 
>bands on SDS polyacrylamide gels with app. mol. wts. of between 50-60 
>KD. As I recall, at least two opinions were provided in responses: 1) 
>contamination due to keratin and 2) a contaminant in 
>b-mercaptoethanol.
>
>I have a student who is experiencing the same problem and we have 
>traced it to either of the above. Can anyone provide references for 
>these annoying bands.
>
>
>
>Dr. Mark Lamkin
>Boston Unversity School of Graduate Dentistry
>
>"Saliva: A little bit goes a long way!"