Ehrlich M, Norris K F, Wang R Y, Kuo K C, Gehrke C W
Biosci Rep. 1986 Apr;6(4):387-93. doi: 10.1007/BF01116426.
The heat-induced conversion of 5-methylcytosine (m5C) residues to thymine residues and of cytosine to uracil residues in single-stranded DNA was studied. The calculated rates for deamination at 37 degrees C and pH 7.4 were approximately 9.5 X 10(-10) and 2.1 X 10(-10) sec-1, respectively. N4-Methyldeoxycytidine, which is in the DNA of certain thermophilic bacteria, was more heat-resistant than was deoxycytidine and much more than was 5-methyldeoxycytidine. Thermophilic bacteria which contain N4-methylcytosine rather than m5C in their genomes may thereby largely avoid heat-induced mutation due to deamination, which is incurred by the many organisms that contain m5C in their DNA.
研究了单链DNA中热诱导的5-甲基胞嘧啶（m5C）残基向胸腺嘧啶残基的转化以及胞嘧啶向尿嘧啶残基的转化。在37℃和pH 7.4条件下计算得到的脱氨速率分别约为9.5×10⁻¹⁰和2.1×10⁻¹⁰秒⁻¹。某些嗜热细菌DNA中的N⁴-甲基脱氧胞苷比脱氧胞苷更耐热，且比5-甲基脱氧胞苷耐热得多。基因组中含有N⁴-甲基胞嘧啶而非m5C的嗜热细菌可能因此在很大程度上避免了因脱氨导致的热诱导突变，而许多DNA中含有m5C的生物体则会发生这种突变。
