need suggestions, protein isolation.

John E. Wiktorowicz johnw at
Mon Nov 29 07:19:47 EST 1999

In our hands, silylation doesn't work. It leaves a polymeric structure
detectable by MS that interferes. Best bet is
not to dry the sample down completely. Good luck

hnasko wrote:

> November 29, 1999
> I hope someone may have some suggestions.  I have isolated a protein >5000
> MW <30,000 MW from cell conditioned media via RP-HPLC.  Sent the sample off
> to a collaborator for sequence analysis and he cannot obtain data.  even
> post trypsin digest the MS gives only peaks of 500-900 Da.  Based on the
> chromatogram and the bioactivity of the sample I know it is there.  The
> magnitude of the peak at 215 and 280 nm suggests there is enough to get
> sequence 4x over.  We guess the problem is adsorption to the plastic
> (untreated tube).  This is the most likly, i would hate to think they dont
> know what they are doing.  Any suggestions as how we might get this protein
> off the tube wall that is compatable with MS?  We are contemplating using a
> detergent like SDS or TritonX followed by an HPLC step (scarry)?  We have no
> structural info about this protein, only a bioactivity.  this tube
> represents 6.5 liters of material and lots of work, I hate to think it is
> lost.  We are going to restart purification with another 2 liters and are
> thinking of ways to treat our tubes to avoid adsorption problems, ie
> siliconization or teflon coated tubes.  I am not sure yet about the
> compatability of the silicon with the MS (any problems there?)  Any
> suggestions regarding these problems would be greatly appreciated.  Also if
> you know a MS/protein core that is really good I am comtemplating trying a
> different group for another sample and would appreciate a reference I could
> contact.
> thanx
> Robert Hnasko
> University of Cincinnati
> College of Medicine
> Dept. Cell biology, Neurobiology and Anatomy
> email:  hnaskor at

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