[RASMB] pH stability

[Jacob Lebowitz]

Dear Yasuaki,

A very long time ago I did alkaline titrations of superhelical DNA 
covering the pH range of 10-12, both band sedimentation velocity and 
buoyant density sedimentation equilibrium experiments. We used 
charcoal filled epon centerpieces and quartz windows. We did not 
encounter any problems. Other labs did alkaline titrations of linear 
DNA without any problems. In preparing the alkaline solutions we 
flowed argon over the solution to prevent CO2 absorption and pH 
shifts. It is also important to adjust the pH of the solution at the 
temperature of the experiment in a temperature controlled vial or 
beaker since there is a significant temperature dependence of the pH. 
With these precautions you should get reproducible results in the titration.

Jack Lebowitz



At 07:34 PM 1/24/2007, Yasuaki Hiromasa wrote:
>Dear RASMB members,
>I am working with peptide/protein at basic condition. I want to 
>characterize it at pH10-12 or 1-10 mM NaOH. Can I apply under these 
>condition to Analytical ultracentrifuge?  Will these base conditions 
>hurt the cell assembly?
>We have aluminum and epon centerpieces. Windows are quartz and sapphire.
>We want to do velocity and equilibrium experiments.
>Has anybody experience at these conditions?
>
>Sincerely,
>Yasuaki HIromasa
>Department od Biochemistry
>Kansas State University
>
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