Abstract
We have found a novel monofunctional thymine glycol-DNA glycosylase in the mouse organs. The activity was purified using the extract prepared from isolated nuclei of mouse liver by repeated high salt extraction. By the use of the extraction buffer containing 0.42M NaCl, most of lower molecular weight proteins including mNTH1 and major APendonuclease, could be separated from the target activity which was extracted more slowly. The specific activity in this extracted fraction was about 300 times higher than that previously observed in nuclear extract. This extracted fraction was further purified using UNO-S1 and UNO-Q1 column (BIO-RAD). The optimum pH and salt condition of the target activity were 100mM KCl and pH 8.0, respectively. The activity was resistant to 0.58 mM EDTA. An apparent single band was observed on SDS-PAGE of active UNO-Q1 fractions. The estimated molecular weight (about 45,200Da) agree with one of candidate proteins observed in previous purification using the extract from isolated nuclei by sonication. [J Radiat Res 44:413 (2003)]
