Reorientation time of DNA molecules in pulsed-field gel electrophoresis

The precise determination of the influence of an electric field strength E on the resolution of DNA molecules during a pulsed-field gel electrophoresis shows that the maximal molecular size Nmax of still resolved DNA molecules is described by the equation Nmax = k tau E alpha, where k is a coefficient, tau is a pulse time, and alpha is an exponent (calculated as approximately 3/2). We assume that the best estimation of the reorientation time tau R for each DNA fragment is such a pulse time in which this DNA molecule is the largest separated one.