Correlations between the midpoint potential and half-wave potential (E
) for HLMW b
and its site-specific mutants. The half-wave potentials (E1/2) were measured at a gold electrode modified with β-mercaptopropionic acid in the presence of 200 μM of poly-L-lysine at 25°C as described in the main text. Midpoint potentials were measured in the absence (line (a)) or presence (line (b)) of 200 μM of poly-L-lysine as described in the main text. Lines were drawn to show the correlations assuming a linear function (f(x) = bx + a). Calculated coefficients and standard deviations are a = 2.945 ± 3.13, b = 0.2863 ± 0.105 for line (a) (with Pearson product-moment correlation coefficient = 0.768 and paired student's t-test value, **P < 0.01), and a = 26.946 ± 8.17, b = 0.59028 ± 0.274 for line (b) (with Pearson product-moment correlation coefficient = 0.706 and paired student's t-test value, **P < 0.01).