[RASMB] dialyzing membranes

[mitrana at mail.utexas.edu]

Hello
For the P-200, we use a round-tip gel loading pipette tips to load the AUC cell.
If running a sedimentation velocity experiment requiring > 200 ul, we piggy-back
the aforementioned 200 ul tip on a 1 ml blue tip (tip slightly cut off) so that
400-450 ul can be pipetted at the same time. Hope this helps Eray.
Mitra

Quoting Frank Niesen <Frank.Niesen at sgc.ox.ac.uk>:

> Hello Eray,
>
> We are very happy using the D-tubes from EMD,
> http://www.merckbiosciences.co.uk/Products/ProductDisplay.asp?catno=71506&
> They are easy to use, and it is (almost) impossible to punch a hole into the
> membrane and loose your protein.
> I usually dialyse a protein sample of higher concentration (~10x) than
> necessary, to fit into one dialyse tube "midi".
> Than I measure the concentration, and then dilute for the samples needed into
> dialysis buffer (the second of consecutively used 2x1 liters; first one to
> discard). The dialysis buffer is also used for the references in AUC.
>
> I am not filling the AUC cells using pipette tips. Rather have all samples
> prepared in Eppendorf tubes (350 ul) and use a syringe with a 1-ml plastic
> needle (FPLC tubing) to fill it all in, in one go. The reason is that I found
> that a volume difference can result from problems with getting the last bit
> of the second go with the P-200 in (because of the air not getting out,
> pressing liquid through on the side of the tip).
>
> I hope you will find these information useful.
> Best regards,
>
>   Frank
>
> Dr. Frank H. Niesen
>
> Chemical Biology
> Structural Genomics Consortium
> University of Oxford
> Botnar Research Centre
> Oxford, OX3 7LD
> United Kingdom
>
> frank.niesen at sgc.ox.ac.uk
> skype ID: frankniesen
> phone +44 (0)1865 737834
> fax      +44 (0)1865 737231
> http://www.sgc.ox.ac.uk/
>
>
> >>> "Eray Dalgakiran" <eraydalgakiran at gmail.com> 14/01/2008 10:22 >>>
> Hi everyone!
>
> I have a couple of questions about sample preparation.
>
> We are using dialysis tubing membranes but is there a practical method for
> dialyzing samples against buffers prior to measurements? What type of
> membranes (company, model etc.) should be used when dealing with protein and
> polymers which their sizes are below 200nm (200kDa)? And how can we be sure
> the samples' concentrations after dialyzing?
>
> What type of tips should we use with Gilson P-200 that are suitable with
> centerpiece holes (company, model etc.)?
>
> Many thanks...
>
>
>
> Eray Dalgakiran
>
> Department of Bioengineering
> Yildiz Technical University
> www.bioeng.yildiz.edu.tr
>
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>


-- 
Mitra S. Rana
Graduate Student
Institute for Cellular and Molecular Biology
2500 Speedway, UT-Austin
Austin, TX-78712