Given by the average of the acid dissociation constants of the ionizable groups in a molecule, FTP, identify this point at which a molecule has no net electric charge.
For a colloid, this point is where the zeta potential of colloidal particles is zero, and is dependent on particle surface properties.  This characteristic can also be used to resolve proteins in an electrophoretic gradient of amphiphilic molecules, a technique known as its namesake "focusing," which is employed as the first dimension in 2D SDS-PAGE.  Molecules near this pH are particularly useful as dilution buffers, although small changes in pH near this point will significantly affect the ionization state of the molecule.  Given by the average of the acid dissociation constants of the ionizable groups in a molecule, FTP, identify this point at which a molecule has no net electric charge.
For a colloid, this point is where the zeta potential of colloidal particles is zero, and is dependent on particle surface properties.  
isoelectric point