Interfacial behavior of thymine, thymidine and thymidine mononucleotides at the mercury-solution interface

Abstract

The adsorption of thymine, thymidine and thymidine mononucleotides has been studied by a differential capacitance method at pH 9 at the dropping mercury electrode. The area occupied by one molecule of thymine adsorbed at the mercury-electrolyte solution interface is 55±2 Å 2 which corresponds closely to the area expected for a thymine molecule adsorbed flat on the electrode surface. The area occupied by thymidine, TMP, TDP and TTP ranges from 100→200 Å 2. This suggests that an appreciable fraction of the electrode surface is covered with deoxyribose or deoxyribosephosphate. In this respect the interfacial behavior of thymidine and thymidine mononucleotides differs significantly from the deoxynucleoside and monodeoxynucleotides of adenine where the deoxyribose or deoxyribosephosphate groups are largely tilted away from the electrode surface.