expressed protein is 5-6kda bigger than

[ae at dna.bio.warwick.ac.uk]

In article <4uv0kv$m8e at nuscc.nus.sg>
 imazhq at leonis.nus.sg (Zheng Huanquan) writes:

>Does anyone have such experience that expressed protein is 5-6kda bigger 
>that native one? my protein is 33kda and has additional 13aa + 6x His, 
>thus the expressed protein should 35-36kda, but I only got 40-42kda 
>expressed. Any explain? 

Perhaps you could indicate the expression vector used.  With the pQE vectors 
we see our proteins increase in size by approximately 7kda.  If this is the 
system you are using then your expressed protein is OK.

Andrew Easton