Yokoyama H, Baraona E, Lieber C S
Alcohol Research Center, Bronx VA Medical Center, New York, NY 10468, USA.
Biochem Biophys Res Commun. 1995 Jul 26;212(3):875-8. doi: 10.1006/bbrc.1995.2050.
The ADH 7 gene, encoding the sigma-alcohol dehydrogenase isozyme, was cloned from a Caucasian genomic DNA library. Comparison of the nucleotide sequence of its exon 7 with that of an ADH 7 previously cloned from a Japanese subject revealed a substitution of the glycine-287 in the Caucasian sigma isozyme with valine in the Japanese. Since a possible mutation at this site could account for ethnic differences in the gastric activity of this isozyme, the frequency of this change was examined in both races. The exon 7 of the ADH 7 was amplified by PCR from 7 Caucasian and 7 Japanese genomic DNA and applied to restriction fragment length polymorphism analysis, using Ava II to digest the sequence encoding glycine-287 and Mae III to digest that encoding valine-287. Regardless of ethnicity, all PCR amplicons were digested by Ava II and none by Mae III, suggesting that the ethnic difference in the 287 amino acid may represent an uncommon mutation, which does not account for the high frequency of minimal activity of the sigma-alcohol dehydrogenase in the Japanese stomach compared to those of non-Orientals.
编码σ-醇脱氢酶同工酶的ADH 7基因是从高加索人基因组DNA文库中克隆出来的。将其外显子7的核苷酸序列与先前从一名日本受试者克隆的ADH 7的核苷酸序列进行比较，发现高加索人σ同工酶中的甘氨酸-287被日本人的缬氨酸取代。由于该位点的可能突变可能解释该同工酶胃活性的种族差异，因此在两个种族中都检测了这种变化的频率。通过PCR从7名高加索人和7名日本人的基因组DNA中扩增ADH 7的外显子7，并将其应用于限制性片段长度多态性分析，使用Ava II消化编码甘氨酸-287的序列，使用Mae III消化编码缬氨酸-287的序列。无论种族如何，所有PCR扩增产物都被Ava II消化，而没有被Mae III消化，这表明287位氨基酸的种族差异可能代表一种罕见的突变，这并不能解释与非东方人相比，日本人胃中σ-醇脱氢酶最低活性的高频率。
