Re: [ccp4bb] Removing PEG3350

2014-08-20 Thread Alexander Aleshin
cbi.nlm.nih.gov/pmc/articles/PMC1304934/ >> >> >> Best wishes, >> Reza >> >> Reza Khayat, PhD >> Assistant Professor >> The City College of New York >> Department of Chemistry, MR-1135 >> 160 Convent Avenue >> New York, NY 10031 &g

Re: [ccp4bb] Removing PEG3350

2014-08-20 Thread Lieh Yoon Low
el. (212) 650-6070 > www.khayatlab.org<http://www.khayatlab.org/> > > > Original message > Date: Wed, 20 Aug 2014 18:57:07 + > From: CCP4 bulletin board > mailto:CCP4BB@JISCMAIL.AC.UK>> (on behalf of Alexander > Aleshin mailto:aales...@sanfordburnh

Re: [ccp4bb] Removing PEG3350

2014-08-20 Thread Alexander Aleshin
ork, NY 10031 Tel. (212) 650-6070 www.khayatlab.org<http://www.khayatlab.org/> Original message Date: Wed, 20 Aug 2014 18:57:07 + From: CCP4 bulletin board mailto:CCP4BB@JISCMAIL.AC.UK>> (on behalf of Alexander Aleshin mailto:aales...@sanfordburnham.org>>) Su

Re: [ccp4bb] Removing PEG3350

2014-08-20 Thread Lieh Yoon Low
3055910/ >>> http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1304934/ >>> Best wishes, >>> Reza >>> Reza Khayat, PhD >>> Assistant Professor >>> The City College of New York >>> Department of Chemistry, MR-1135 >>> 160 Conv

Re: [ccp4bb] Removing PEG3350

2014-08-20 Thread Alexander Aleshin
www.khayatlab.org<http://www.khayatlab.org> Original message Date: Wed, 20 Aug 2014 18:57:07 + From: CCP4 bulletin board mailto:CCP4BB@JISCMAIL.AC.UK>> (on behalf of Alexander Aleshin mailto:aales...@sanfordburnham.org>>) Subject: Re: [ccp4bb] Removing PEG335

Re: [ccp4bb] Removing PEG3350

2014-08-20 Thread Roger Rowlett
2014 18:57:07 + From: CCP4 bulletin board (on behalf of Alexander Aleshin ) Subject: Re: [ccp4bb] Removing PEG3350 To: CCP4BB@JISCMAIL.AC.UK I meant application of GF as an ion exchange column. Oh, my goodness! Ion exchange is something else! It should read "buffer-ex

Re: [ccp4bb] Removing PEG3350

2014-08-20 Thread Petri Kursula
Hi, There is a gray area, where you would refrain from talking about low-MW contaminants. PEG3350 will be a highly elongated polymer, with way higher hydrodynamic radius than a globular molecule of the same MW. It also will bind a lot of H2O. Hence, it might not go through concentrators (but co

Re: [ccp4bb] Removing PEG3350

2014-08-20 Thread Reza Khayat
. (212) 650-6070 www.khayatlab.org Original message >Date: Wed, 20 Aug 2014 18:57:07 + >From: CCP4 bulletin board (on behalf of Alexander >Aleshin ) >Subject: Re: [ccp4bb] Removing PEG3350 >To: CCP4BB@JISCMAIL.AC.UK > > I meant application of GF as an ion

Re: [ccp4bb] Removing PEG3350

2014-08-20 Thread Alexander Aleshin
I meant application of GF as an ion exchange column. Oh, my goodness! Ion exchange is something else! It should read "buffer-exchange" = desalting column. On Aug 20, 2014, at 11:48 AM, Alexander Aleshin wrote: Dear Remie, I meant application of GF as an ion exchange column. You can use special io

Re: [ccp4bb] Removing PEG3350

2014-08-20 Thread Alexander Aleshin
Dear Remie, I meant application of GF as an ion exchange column. You can use special ion exchange columns, but our lab often uses preparative GF columns for this task. We just load the column, keeping sample volume < the void volume. Thus, we do not concentrate a protein before an ion exchang

Re: [ccp4bb] Removing PEG3350

2014-08-19 Thread Remie
Hi Alex, I disagree with you even though GF is always the last step in my purifications. Because it involves concentration before and after the GF so during the concentration you can already be doing the buffer exchange. You use GF when you want to purify other protein impurities if they are di

Re: [ccp4bb] Removing PEG3350

2014-08-19 Thread R. M. Garavito
Reza, If your protein is not too small (>20 kDa), use a spin-column (i.e., desalting column) with G-25 sephedex. It is CHEAP, fast, and the recovery is good. We have even used them to adjust buffer concentrations or to remove micellar detergents; we have used protein concentrations up to 10 m

Re: [ccp4bb] Removing PEG3350

2014-08-19 Thread Alexander Aleshin
Remie, Actually, concentrating of a protein solution is not the best approach to removing low MW impurities, gel filtration chromatography is more reliable and ... faster. Regards, Alex On Aug 19, 2014, at 7:03 AM, Remie Fawaz-Touma wrote: Hi Reza, I had to do this before. This protocol work

[ccp4bb] Removing PEG3350

2014-08-19 Thread Reza Khayat
Hi, Does anyone have a protocol for getting rid of PEG3350 from a protein sample? Best wishes, Reza Reza Khayat, PhD Assistant Professor The City College of New York Department of Chemistry, MR-1135 160 Convent Avenue New York, NY 10031 Tel. (212) 650-6070 www.khayatlab.org

Re: [ccp4bb] Removing PEG3350

2014-08-19 Thread Remie Fawaz-Touma
Hi Reza, I had to do this before. This protocol works for any PEG and any chemical to be removed from a solution: buffer exchange into the new buffer you want your protein to be in. There are ways to do that by 15 mL Amicon concentrators from millipore for large volumes, or if your protein is

Re: [ccp4bb] Removing PEG3350

2014-08-19 Thread Keller, Jacob
CP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] Removing PEG3350 Hi, Does anyone have a protocol for getting rid of PEG3350 from a protein sample? Best wishes, Reza Reza Khayat, PhD Assistant Professor The City College of New York Department of Chemistry, MR-1135 160 Convent Avenue New York, NY 10031 Tel.