Ikuta T, Szeto S, Yoshida A
Proc Natl Acad Sci U S A. 1986 Feb;83(3):634-8. doi: 10.1073/pnas.83.3.634.
Class I human alcohol dehydrogenase (ADH; alcohol:NAD+ oxidoreductase, EC 1.1.1.1) consists of several homo- and heterodimers of alpha, beta, and gamma subunits that are governed by the ADH1, ADH2, and ADH3 loci. We previously cloned a full length of cDNA for the beta subunit, and the complete sequence of 374 amino acid residues was established. cDNAs for the alpha and gamma subunits were cloned and characterized. A human liver cDNA library, constructed in phage lambda gt11, was screened by using a synthetic oligonucleotide probe that was matched to the gamma but not to the beta sequence. Clone pUCADH gamma 21 and clone pUCADH alpha 15L differed from beta cDNA with respect to restriction sites and hybridization with the nucleotide probe. Clone pUCADH gamma 21 contained an insertion of 1.5 kilobase pairs (kbp) and encodes 374 amino acid residues compatible with the reported amino acid sequence of the gamma subunit. Clone pUCADH alpha 15L contained an insertion of 2.4 kbp and included nucleotide sequences that encode 374 amino acid residues for another subunit, the alpha subunit. In addition, this clone contained the sequences that encode the COOH-terminal part of the beta subunit at its extended 5' region. The amino acid sequences and coding regions of the cDNAs of the three subunits are very similar (approximately 93-95% identity). A high degree of resemblance is observed also in their 3' noncoding regions. However, distinctive differences exist in the vicinity of the Zn-binding cysteine residue at position 46--i.e., Cys-Gly-Thr in the alpha, Cys-Arg-Thr in the wild-type beta 1, Cys-His-Thr in the Oriental-type beta 2, and Cys-Arg-Ser in the gamma, reflecting the differences in their kinetic properties. Based on the cDNA sequences and the deduced amino acid sequences of the three subunits, their structural and evolutionary relationships are discussed.
I类人酒精脱氢酶（ADH；酒精：NAD+氧化还原酶，EC 1.1.1.1）由α、β和γ亚基的几种同二聚体和异二聚体组成，这些亚基由ADH1、ADH2和ADH3基因座控制。我们之前克隆了β亚基的全长cDNA，并确定了374个氨基酸残基的完整序列。α和γ亚基的cDNA被克隆并进行了表征。使用与γ序列匹配但与β序列不匹配的合成寡核苷酸探针筛选了构建在噬菌体λgt11中的人肝脏cDNA文库。克隆pUCADHγ21和克隆pUCADHα15L在限制性酶切位点和与核苷酸探针的杂交方面与βcDNA不同。克隆pUCADHγ21包含一个1.5千碱基对（kbp）的插入片段，编码374个氨基酸残基，与报道的γ亚基氨基酸序列相符。克隆pUCADHα15L包含一个2.4 kbp的插入片段，包括编码另一个亚基α亚基374个氨基酸残基的核苷酸序列。此外，该克隆在其延伸的5'区域包含编码β亚基COOH末端部分的序列。三个亚基的cDNA的氨基酸序列和编码区域非常相似（约93 - 95%的同一性）。在它们的3'非编码区域也观察到高度相似性。然而，在第46位与锌结合的半胱氨酸残基附近存在明显差异——即α亚基中为Cys-Gly-Thr，野生型β1中为Cys-Arg-Thr，东方型β2中为Cys-His-Thr，γ亚基中为Cys-Arg-Ser，这反映了它们动力学性质的差异。基于三个亚基的cDNA序列和推导的氨基酸序列，讨论了它们的结构和进化关系。
