THERMODYNAMICS OF NUCLEIC-ACID BASES AND NUCLEOSIDES IN WATER FROM 25-DEGREES-C TO 55-DEGREES-C

Abstract

Specific heat capacities, apparent molar heat capacities, densities, and ap parent molar volumes have been determined for cytosine, uracil, thymine, adenine, cytidine, 2'-deoxycytidine, uridine, thymidine and adenosine at temperatures from 25 degrees C to 55 degrees C. The results of these measurements have been used to calculate for the first time, the thermodynamic quantities: C-p,2(o), (partial derivative C-p,2(o)/partial derivative T)(p), (partial derivative(2)C(p,2)(o)/partial derivative T-2)(p), V-2(o), (partial derivative V-2(o)/partial derivative T)(p), and (partial derivative(2)V(2)(o)/partial derivative T-2)(p). The -CH2- group contribution has been calculated at different temperatures. It has also been observed from the data for the nucleic acid bases and nucleosides that the additivity rule C-p,2(o)(nucleoside) - C-p,2(o)(base) + C-p,2(o)(water) = C-p,2(o)(ribose) does not hold in these cases.