Apparent MW of protein on PAGE gel
beavis at newton.physics.mun.ca
Thu Mar 10 07:41:13 EST 1994
In article <1994Mar9.202838.15613 at wmichgw> ou_lehrman at wmich.edu (Russ_Lehrman) writes:
>> A fusion protein I expressed in E. coli has a apparent MW on SDS-PAGE gel ~5
>> kdlager than it's calculated MW. This protein is 303 aa residues with
>> acalculated MW of 35 kd but it runs at 40 kd position on SDS-PAGE. The
>> proteinhas very high content of basic amino acids (32 lysines, 20 arginine
>> and 16histidines). My question is : does high content of basic residues make
>> aprotein run slower?I would apreciate very much any hints to my question.
It is not unusual for basic (or acidic) proteins to run on SDS-PAGE with
apparent MW's significantly different from their true chemical molecular
mass. If you are really concerned about this apparent mass shift, send a
sample out for mass spectrometry.
Memorial University of Newfoundland
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