Proteins which run high on SDS-PAGE

Mon May 13 06:47:35 EST 1996

On Wed, 8 May 1996 13:15:56 GMT Sam Simons said:
>Prolines introduce natural "kinks" in the protein which aren't
>straightened out by denaturing. Since denaturing in SDS creates linear
>polypeptides, this bending will give a larger stokes radius to the
>protein which will cause it to run slower through SDS-PAGE.
Would you like to elaborate on that?  It seems contrary to what I recall
about f for long rods as opposed to ellipsoids or spheres.  Isn't the
rod an 'extreme' case, such that any alteration of the shape would
decrease f?  As I suggested to the original poster, the possibility of
charge anomaly (i.e. extra +'s) is far more likely, and would not require
something completely out of line with the size range we're dealing with
in this case.  Nevertheless, If someone can show that
|          moves more slowly than  ___________________, I'd like to see it.
|          I'd be _really_ surprised (not the first time) to see that
|________          _   _
            ______| |_| |____   would run more slowly.

|                              O==O                            |
|  DAVID G. RHODES             O==O  PHONE 860-486-5413        |
|  SCHOOL OF PHARMACY; U-92    O==O  FAX   860-486-4998        |
|  UNIVERSITY OF CONNECTICUT   O==O                            |
|  STORRS, CT  06269-2092      O==O  RHODES at UCONNVM.UCONN.EDU  |
|                              O==O                            |

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