Dependence of the mobilities and mobility ratios observed for small polyion charge variants on: (A) and (C), the fractional charge of the polyion; and (B) and (D), the logarithm of the fractional charge. The symbols in all panels correspond to: (o), benzene charge variants; (■,△), naphthalene charge variants; (▽), adenosine charge variants; and (●), seven-residue peptides (see Table 1). The straight lines in (B) connect the mobilities of the charge variants of each polyion and are meant to guide the eye. The straight line in (D) was drawn by linear regression; r2 = 0.966.