Phi Value Analysis - Errors Associated With -value Analysis

Errors Associated With -value Analysis

Experimental errors can be high in measuring equilibrium stability as well the folding/unfolding rates in water for the wild-type protein and mutants. The necessity of extrapolating phi values in pure water from measurements made in solutions containing denaturants adds uncertainty to the reported values. When the stability difference between the native and mutant protein are low (< 7 kJ/mol), experimental error can be very large; unusual phi-values outside the 0-1 range may arise from these errors rather than illustrating deviations from the conditions assumed by the method. In addition, calculated phi values have been shown to depend strongly on the number of data points collected and the laboratory in which the experiment was performed.