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

Ron Beavis beavis at
Wed Mar 9 14:45:47 EST 1994

In article <CMDqJ6.H96 at> ez007215 at ALCOR.UCDAVIS.EDU writes:
>In article <2lg6vo$9s7 at>, bhuang at (Baohua Huang) writes:
>>Hi, everyone.
>>A fusion protein I expressed in E. coli has a apparent MW on SDS-PAGE gel ~5 kd
>>lager than it's calculated MW. This protein is 303 aa residues with a 
>>calculated MW of 35 kd but it runs at 40 kd position on SDS-PAGE. The protein 
>>has very high content of basic amino acids (32 lysines,  20 arginine and 16 
>>histidines). My question is : does high content of basic residues make a 
>>protein run slower?
>>I would apreciate very much any hints to my question.
>>Baohua Huang
>>Ohio state Univ.
>Is it possible that the protein has been modified posttranslationally, such as 
>phosphorylation etc.

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