Apparent MW of protein on-PAGE gel > real MW?

[FRIST at wvnvm.wvnet.edu]

In article <2lg6vo$9s7 at charm.magnus.acs.ohio-state.edu>,
bhuang at magnus.acs.ohio-state.edu (Baohua Huang) says:
>







>             My question is : does high content of basic residues make a
>protein run slower? (on SDS gels)

In a word, Yes.  SDS will sequester the native charge of most proteins but if
 there is a high net charge the migration rate will be off the plot of the
standards.  Years ago (unpublished) I noticed that succinylated proteins run
faster than corresponding unmodified proteins on SDS gels.    R. Frist