[RASMB] peptide in DMSO (2)

[Leech, AP]

Sorry, I should have looked up the paper referenced by Arthur
in the archives before writing (Richard F Tester, Trushar Patel
& Stephen E Harding (2006) "Damaged starch characterisation by
ultracentrifugation" Carb Res 341 130-137). They used the
interference optics with 8 mg/ml starch solutions. Perhaps
someone could comment on whether more dilute solutions would
be usable?

Andrew

Leech, AP wrote:
> Hi all,
> 
> Can I be the first to point out the viscosity of DMSO? I don't
> have accurate figures but a quick web search implies >2 cp
> (twice that for water) and variable with water content of the
> mixture. The other thing is, how will you detect your peptide?
> DMSO has quite a high UV absorbance so you might have difficulty
> if your peptide doesn't have a decent extinction coefficient.
> (Has anyone ever tried the interference optics with DMSO?)
> 
> Andrew
> 
> Tom Laue wrote:
>> Hi Christine-
>> A couple of things to keep in mind-
>> The buoyancy of your peptide will be very small in 90% DMSO. See what 
>> Steve, et al. used for the density at 90%.
>> DMSO is compressible, so you may need to include compressibility in 
>> your calculations (depending on rotor speed)
>> Finally, DMSO is not entirely innocuous with epoxy. Your centerpieces 
>> may get softened.
>> Best wishes,
>> Tom
>>
>> Schar, Christine wrote:
>>> Hi
>>> I was hoping to get some advice about running a peptide (24mer, 2787 Da)
>>> in 90% DMSO. I searched the archives and found Harding has used 90% DMSO
>>> successfully for carbohydrates (not peptides) so I know my centerpieces
>>> won’t melt at least.
>>>
>>> The group I’m working with used this peptide in NMR.  They didn’t get a
>>> good signal in PBS so they switched to DMSO.  They’re seeing NOEs and 
>>> they
>>> are interested in knowing if their peptide aggregates.  Another
>>> possibility is it forms micelles.  Is it feasible to try a run with this
>>> peptide in DMSO?  Are there any special considerations?
>>>
>>> Thanks for any help.
>>> Christine Schar
>>>
>>>
>>> _______________________________________________
>>> RASMB mailing list
>>> RASMB at rasmb.bbri.org
>>> http://rasmb.bbri.org/mailman/listinfo/rasmb
>>>
>>>   
>>
> 

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