Comments on "Calculation of the energy of transition associated with inversions in double-stranded DNA" [P. Aggarwal, D. Dollimore, Thermochim. Acta 284 (1996) 109]: a test

An alternative kinetic model of DNA melting curves, rising temperature kine tic evaluation, was recently suggested [Thermochim. Acta 284 (1996) 109] an d applied to UV melting profiles of duplex DNA oligomers. We have investiga ted this kinetic model and compared it with the two-state thermodynamic equ ilibrium model. UV melting profiles for native DNA duplex oligomers were co llected at various heating and cooling rates. Experimental melting curves o f duplex DNA oligomers were found to be reversible and independent of the h eating rates in range from 2.5 to 45 degreesC h(-1). When the melting curve s were evaluated in the terms of the alternative kinetic model, specific ki netic rate constants for duplex denaturation depended on the heating rates. These results indicate that native DNA duplex oligomers exhibit equilibriu m melting transitions and the suggested kinetic model is invalid for meltin g profiles of native DNA duplex oligomers collected at the studied range of heating rates. (C) 2001 Elsevier Science B.V. All rights reserved.