Lomri N, Gu Q, Cashman J R
Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco 94143-0446.
Proc Natl Acad Sci U S A. 1992 Mar 1;89(5):1685-9. doi: 10.1073/pnas.89.5.1685.
Complementary DNA (cDNA) clones encoding the adult human liver flavin-containing monooxygenase (FMO; dimethylaniline N-oxidase, EC 1.14.13.8) were isolated from lambda gt10 and lambda gt11 libraries. The cDNA libraries were screened with three synthetic 36-mer oligonucleotide probes derived from the nucleic acid sequence of the pig liver FMO cDNA. The deduced amino acid sequence for the adult human liver FMO was quite distinct from the pig liver FMO, and adult human liver FMO was designated form II (HLFMO II). The full-length cDNA sequence of HLFMO II [2119 base pairs (bp)] had an open reading frame of 1599 nucleotides, which encoded a 533-amino acid protein of Mr 59,179, a 5'-noncoding region of 136 nucleotides and a 3'-noncoding region of 369 nucleotides excluding the poly(A) tail. The deduced amino acid sequence of HLFMO II had 80% similarity with the rabbit liver FMO II but only a 52%, 55%, and 53% amino acid similarity with the rabbit liver (form I), the pig liver (form I), and fetal human liver (form I) FMOs, respectively. RNA analysis of adult human liver RNA showed that there was one HLFMO II mRNA species. Analysis of genomic DNA indicated that HLFMO II was the product of a single gene. These results indicated that the deduced amino acid sequence for HLFMO II contained highly conserved residues and suggested that FMO enzymes were closely related and, undoubtedly, derived from the same ancestral gene.
从λgt10和λgt11文库中分离出编码成人肝脏含黄素单加氧酶（FMO；二甲基苯胺N-氧化酶，EC 1.14.13.8）的互补DNA（cDNA）克隆。用从猪肝FMO cDNA核酸序列衍生的三种合成36聚体寡核苷酸探针筛选cDNA文库。成人肝脏FMO推导的氨基酸序列与猪肝FMO有很大不同，成人肝脏FMO被命名为II型（HLFMO II）。HLFMO II的全长cDNA序列[2119个碱基对（bp）]有一个1599个核苷酸的开放阅读框，编码一个533个氨基酸、Mr为59,179的蛋白质，一个136个核苷酸的5'-非编码区和一个369个核苷酸的3'-非编码区（不包括聚腺苷酸尾）。HLFMO II推导的氨基酸序列与兔肝FMO II有80%的相似性，但与兔肝（I型）、猪肝（I型）和胎儿人肝（I型）FMO的氨基酸相似性分别仅为52%、55%和53%。成人肝脏RNA的RNA分析表明有一个HLFMO II mRNA种类。基因组DNA分析表明HLFMO II是单个基因的产物。这些结果表明HLFMO II推导的氨基酸序列含有高度保守的残基，并提示FMO酶密切相关，无疑源自同一个祖先基因。
