IEF unit recommendations.

Dr Engelbert Buxbaum engelbert_buxbaum at
Sat Jun 12 09:29:04 EST 2004

Sean Patterson wrote:

> > Note that in my application (denauring IEF of transmembrane
> > proteins) 10,000 Vh proved insufficient for complete focussing,
> > 25,000 Vh worked a lot better. YMMV.
> How did you manage that if the power supply is integral to the unit
> and rated to 10,000V? Or were the specifications/design different in
> the first unit?

Thats Volt*hours, not Volts. If you apply 10,000 V for 2 hours, you get
20,000 Vh. The higher the voltage and the longer the time, the higher
the likelyhood that proteins have achieved their equilibrium position.
On the down side, problems like electroendosmosis tend to increase too.

Pharmacia has published a booklet on IEF, that explains these things
fairly well. IIRC, you can get it as PDF from their web site.

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