SDS PAGE and phosphorylation

Dima Klenchin klenchin at
Wed Jul 31 00:43:27 EST 1996

In article <4tmeof$5s6 at>, rfeldber at (Ross S Feldberg) wrote:
#  I am curious if anyone knows why phosphorylated proteins can be 
#separated from their non-phosphorylated forms on SDS gels. I would assume 
#that the introduction of 1 or 2 more negative charges wouldn't have a 
#significant effect on a protein that has a large amount of SDS already 
#bound. Can anyone point me to a review article or techniques article 
#which discusses this ?  thanks

1) Don't know the answer. Wild guess would be not charge (if anything, 
additional "-" would make it run faster while usually they are slowed 
down), but shape and/or SDS binding. 

2) Wish to point out that if you imply that this is a general case, then 
it's wrong. As a matter of fact, most proteins _do not_ change their SDS 
PAGE behavoir upon phosphorylation. Only relatively few 
proteins (that become celebrated cases and created widespread 
generalization) do.  

- Dima

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