• 作者： 趙有誠; 劉先仁; 蔡秀鳳; 尹士俊
• 作者服務機構： 三軍總醫院內科部胃腸科; 三軍總醫院醫學研究部; 國防醫學院生化學科
• 中文摘要： 約半數中國人缺失參與酒精代謝所產生乙醛之氧化的粒線體酸脫氫?2(ALDH2)的活性。這項缺失造成酒精性臉紅
  反應，是國人酒精依賴之負危險生物因子。為評估突變型ALDH對偶基因所製造之失活型ALDH2次單元在四次單元
  ?分子催化反應中的效應，我們應用瓊膠等電集集電泳鑑定30例國人胃內視鏡活檢體之ALDH2表現型及應用聚合?連
  鎖反應擴增法和對偶基因專一性寡核?酸探針雜交法來測定同一人白血球之ALDH基因型。16人屬ALDH同型接合
  子，1人屬ALD，同型接合子，13人屬異型接合子。不論突變型ALDH同型接合子或異型接合子均不表現ALDH2活
  性帶或位於ALDH 1和ALDH2間的中間型活性帶。我們的結果顯示突變型基因呈顯性，含突變型次單元之ALDH2四次
  單元分子不具?活性或僅具極低之活性。
  m
• 英文摘要： About half of Chinese individuals lack mitochondrial aldehyde dehydrogenase-2 (ALDH2) activity,which is responsible for the oxidation of acctaldehyde produced during ethanol metabolism. The ALDH2deficiency in Chinese has been implicated in alcohol flush reaction and reported to be a negative risk factorfor development of alcohol dependence. To assess the effects of inactive ALDH2 subunits, encoded bythe mutant ALDH allele, on the catalytic activity of tetrameric enzyme molecules, we have phenotypedALDH2 from 30 gastroendoscopic biopsies by using agarose isoelectric focusing and determined the geno-types from leukocytes of the same individuals by using polymerase-chain-reaction amplification and hy-bridization with allele-specific oligonucleotide probes. Sixteen subjects were homozygous for the ALDHallele, one was homozygous for ALDH, and thirteen were the heterozygous genotype. None of the sub-jects with the mutant homozygotic and the heterozygotic genotypes exhibited the ALDH2 activity band orintermediate bands between ALDH2 and ALDH1 on isolectric focusing gels. Our results support the notionthat the mutant allele is dominant and that the heterotetrameric ALDH2 molecules containing the mutantsubunits are enzymatically inactive or far less active.
• 中文關鍵字： human; aldehyde dehydrogenase-2; genotype; phenotype; dominance
• 英文關鍵字： --