Hydrolysis of N3-methyl-2'-deoxycytidine: model compound for reactivity of protonated cytosine residues in DNA.

Published

Journal Article

Protonation of cytosine residues at physiological pH may occur in DNA as a consequence of both alkylation and aberrant base-pair formation. When cytosine derivatives are protonated, they undergo hydrolysis reactions at elevated rates and can either deaminate to form the corresponding uracil derivatives or depyrimidinate generating abasic sites. The kinetic parameters for reaction of protonated cytosine are derived by studying the hydrolysis of N3-methyl-2'-deoxycytidine (m3dC), a cytosine analogue which is predominantly protonated at physiological pH. Both deamination and depyrimidimation reaction rates are shown to be linearly dependent upon the fraction of protonated molecules. We present here thermodynamic parameters which allow determination of hydrolysis rates of m3dC as functions of pH and temperature. Protonation of cytosine residues in DNA, as induced by aberrant base-pair formation or base modification, may accelerate the rate of both deamination and depyrimidation up to several thousand-fold under physiological conditions.

Full Text

Duke Authors

Cited Authors

  • Sowers, LC; Sedwick, WD; Shaw, BR

Published Date

  • November 1989

Published In

Volume / Issue

  • 215 / 1

Start / End Page

  • 131 - 138

PubMed ID

  • 2811913

Pubmed Central ID

  • 2811913

Electronic International Standard Serial Number (EISSN)

  • 1873-135X

International Standard Serial Number (ISSN)

  • 0027-5107

Digital Object Identifier (DOI)

  • 10.1016/0027-5107(89)90225-x

Language

  • eng