IUBio Biosequences .. Software .. Molbio soft .. Network News .. FTP

Best way to adjust pH of a protein?

Robert Burns burns at sasa.gov.uk
Tue Jul 19 06:04:27 EST 1994

"Andrew, Tel. +39-6-91093434" <WALLACE at IRBM.IT> wrote :

>Jim Owens <jow at helix.nih.gov> wrote:
>>I found this posted on bionet.molbio.methds-reagnts and thought it 
>>properly belongs on bionet.molbio.proteins:
>>In article <305vv0$754 at news.iastate.edu> Bipin K Dalmia,
>>bipin at iastate.edu writes:
>>>what is the best way (quickest) to adjust the pH of a protein 
>>>dialysis takes too long and desalting/buffer exchange columns are 
>>>'cause i have 100 mL of solution and it would take a 10-story high
>>>column. directly adding acid/base would cause extreme local pH 
>>>and denature the protein. 
>>>i have to do this prior to running an ion-exchange column so i 
>>>increase the ionic-strength too much either.
>>I wonder about the answer I posted:
>[good ideas deleted]
>I agree with Jim's suggestions and would add the following 
>If Bipin K Dalmia has access to a hollow-fibre concentrator this 
might be
>a gentler way of concentrating the sample prior to diluting with the 
>exchange loading buffer. Such devices can easily handle 100 ml of 
>Only thing is that the original poster didn't say what the 
>of the protein in the 100 ml of solution was, so any treatment to 
>the sample may cause precipitation of the protein if you already 
start from
>a high value. This may or may not be a problem, no way to tell 
without more
>Andrew <wallace at irbm.it>

How about concentrating using a stirred cell under nitrogen gas,
"Filtron" make a good cheap one.Again as above the concentration
step might affect the protein depending on its starting conc.

Robert <burns at sasa.gov.uk> 

More information about the Methods mailing list

Send comments to us at biosci-help [At] net.bio.net