Synthesis of an hydrophilic, pK 8.05 buffer for isoelectric focusing in immobilized pH gradients.

The synthesis of a new, pK 8.05 acrylamido weak base for isoelectric focusing in immobilized pH gradients (IPG) is here reported. This compound N,N-bis(2-hydroxyethyl)-N'-acryloyl-1,3-diaminopropane is strongly hydrophilic, and thus inhibits any potential hydrophobic interaction among proteins and the grafted basic groups in an IPG matrix. In addition, this novel buffer represents a step ahead towards the goal of closing the 'gap' between the commercially available Immobilines, pK 7.0 and 8.5. Owing to the large distance between these two neighboring pK values, it is difficult to arrange for linear narrow pH gradients in this region. IPG compositions obtained with this new buffer give highly linear pH gradients and protein profiles identical to those obtained with commercial Immobilines.