A novel matrix consisting of N-acryloylaminoethoxyethanol, a hydrophilic monomer extremely resistant to hydrolysis, was recently reported by Chiari et al. (Electrophoresis, 1994, 15, 177-186). When using it as a matrix for grafting immobilized pH gradients for isoelectric focusing, a shift in protein spot position was noticed. This was attributed to a shift in ph values of the Immobiline buffers when changing from the standard poly(acrylamide) to a poly(N-acryloylaminoethoxyethanol) matrix. A series of 1 pH unit gradients was constructed, where a single buffering Immobiline was used and titrated with a counterion having a ph removed by at least 3 pH units from the nearest extreme of the generated pH interval. It was noted that all compounds became weaker acids and bases, with a Delta pK ranging from -0.02 to -0.06 for the acids (pK 3.6, 4.4, and 4.6) and a Delta pK ranging from -0.12 tp -0.20 for the bases. The new pK values for the seven commercially available buffers are thus pK 3.6 -> pK 3.58, ph 4.4 -> pK 4.36, pK 4.51 -> 4.45, pK 6.21 -> 6.09, ph 7.06 -> 6.94, ph 8.50 -> pK 8.37, and pK 9.59 -> pK 9.39. These values refer to 10 degrees C in the gel phase, the first value in poly(acrylamide) and the second in poly(N-acryloylaminoethoxyethanol).
Immobilized pH gradients: new pK values of acrylamido buffers in poly(N-acryloylamino ethoxy ethanol) matrices.
BOSSI, Alessandra Maria;
1994-01-01
Abstract
A novel matrix consisting of N-acryloylaminoethoxyethanol, a hydrophilic monomer extremely resistant to hydrolysis, was recently reported by Chiari et al. (Electrophoresis, 1994, 15, 177-186). When using it as a matrix for grafting immobilized pH gradients for isoelectric focusing, a shift in protein spot position was noticed. This was attributed to a shift in ph values of the Immobiline buffers when changing from the standard poly(acrylamide) to a poly(N-acryloylaminoethoxyethanol) matrix. A series of 1 pH unit gradients was constructed, where a single buffering Immobiline was used and titrated with a counterion having a ph removed by at least 3 pH units from the nearest extreme of the generated pH interval. It was noted that all compounds became weaker acids and bases, with a Delta pK ranging from -0.02 to -0.06 for the acids (pK 3.6, 4.4, and 4.6) and a Delta pK ranging from -0.12 tp -0.20 for the bases. The new pK values for the seven commercially available buffers are thus pK 3.6 -> pK 3.58, ph 4.4 -> pK 4.36, pK 4.51 -> 4.45, pK 6.21 -> 6.09, ph 7.06 -> 6.94, ph 8.50 -> pK 8.37, and pK 9.59 -> pK 9.39. These values refer to 10 degrees C in the gel phase, the first value in poly(acrylamide) and the second in poly(N-acryloylaminoethoxyethanol).
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
