His-tagged protein and SDS-PAGE migration

David R. Bell david.bell at nottingham.ac.uk
Mon Mar 30 17:41:58 EST 1998


The same thing is true for just about all cytochromes P450: they
typically have an Mr of 58-60 kDa, and migrate at 52kDa by 
SDS-PAGE. 
P450s are not tremendously hydrophobic although they do live in the
endoplasmic reticulum. So aberrant migration is quite likely if an
introduced domain interrupts tertiary structure or a hydrophobic domain.



On Fri, 27 Mar 1998 12:55:43 -0800, Dr E. Buxbaum wrote:

:>> (although I've never seen a protein migrate faster than expected
:>> on SDS-PAGE... how about anyone else?)
:>
:>That can happen with very hydrophobic proteins (for example
:>transmembrane proteins), which bind more SDS than they should for their
:>size. A typical example would be the Na/K-ATPase alpha subunit, which
:>has a MW of 114 (from sequence), but runs at about 80 kDa.






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