Hur M W, Ho W H, Brown C J, Goldman D, Edenberg H J
Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202-5122.
DNA Seq. 1992;3(3):167-75. doi: 10.3109/10425179209034012.
We have cloned and sequenced a cDNA encoding the mouse class III alcohol dehydrogenase, Adh-B2. Adh-B2 mRNA is detectable in all the mouse tissues tested. Class III ADHs are highly conserved: the deduced amino acid sequence of the mouse Adh-B2 is 91 to 97% identical to the human, horse and rat liver enzymes. The mouse Adh-B2 cDNA is 87% identical in nucleotide sequence to the human chi-ADH cDNA. Previously, a slower rate of evolutionary divergence of the amino acid sequences of class III ADH proteins was detected and ascribed to functional constraints upon the protein. Our analysis of the nucleotide sequences demonstrates that this cannot be the entire explanation, since the rate of silent (synonymous) nucleotide substitutions is also lower in the class III ADHs than in the class I ADHs.
我们已经克隆并测序了编码小鼠Ⅲ类乙醇脱氢酶（Adh-B2）的cDNA。在所有检测的小鼠组织中均可检测到Adh-B2 mRNA。Ⅲ类乙醇脱氢酶高度保守：小鼠Adh-B2推导的氨基酸序列与人类、马和大鼠肝脏中的酶有91%至97%的同一性。小鼠Adh-B2 cDNA在核苷酸序列上与人类chi-ADH cDNA有87%的同一性。此前，已检测到Ⅲ类乙醇脱氢酶蛋白质氨基酸序列的进化分歧速率较慢，并归因于该蛋白质上的功能限制。我们对核苷酸序列的分析表明，这并非全部原因，因为Ⅲ类乙醇脱氢酶中沉默（同义）核苷酸替换的速率也低于Ⅰ类乙醇脱氢酶。
