Molecular basis for the polymorphic forms of human serum paraoxonase/arylesterase: glutamine or arginine at position 191, for the respective A or B allozymes.
Molecular basis for the polymorphic forms of human serum paraoxonase/arylesterase: glutamine or arginine at position 191, for the respective A or B allozymes.
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发表时间：
1993-03
影响因子：
9.8
通讯作者：
S. Adkins;K. Gan;Malay Modyt;B. Dut
中科院分区：
文献类型：
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作者：
S. Adkins;K. Gan;Malay Modyt;B. Dut
对氧磷酶/芳基酯酶基因位于 7 号染色体上靠近囊性纤维化基因的位置。人血清中含有两种对氧磷酶/芳基酯酶同种酶 A 和 B，它们的底物特异性和动力学特性不同。用胰蛋白酶消化纯化的 A、AB 和 B 酯酶，并通过高效液相色谱法对所得肽进行比较。所有三个样品的洗脱曲线都非常相似，除了 (1) 仅在 A 和 AB 曲线中看到的一种肽（即肽 A）和 (2) 仅在 B 和 AB 曲线中看到的另一种肽（即肽 B）。测序显示，肽 A 在氨基酸位置 191 处具有谷氨酰胺，而肽 B 是通过位置 191 的羧基侧裂解产生的，大概是因为该位置存在碱性（胰蛋白酶特异性）氨基酸。我们的实验室和另一家实验室独立工作，对人肝脏 cDNA 文库中的对氧磷酶编码区进行了测序，并鉴定了两个多态性位点：位置 191 的 Arg/Gln 和位置 54 的 Leu/Met。使用 PCR 扩增和基因组 DNA 两个多态性区域中的核苷酸直接测序，我们估计了等位基因频率，并确定了它们与 27 名无关成人和成年患者血清对氧磷酶同种异型酶表型的一致性。三代血统的16名成员。在无关个体中，第 54 位的 Met/Leu 多态性与血清酯酶表型不相关。相反，191位的特定氨基酸与血清表型完全相关：A型个体在191位具有Gln，而B型个体在191位具有Arg；仅在杂合 (Arg/Gln) 组合中发现了 AB 型血清。谱系分析显示这两个多态性均以预期的孟德尔方式遗传，并证实只有 191 个多态性与血清对氧磷酶/芳基酯酶表型一致。
The paraoxonase/arylesterase gene is located close to the cystic fibrosis gene on chromosome 7. Human serum contains two paraoxonase/arylesterase allozymes, A and B, which differ in their substrate specificities and kinetic properties. Purified A, AB, and B esterases were digested with trypsin, and the resultant peptides were compared by high-performance liquid chromatography. The elution profiles were very similar for all three samples, except for (1) one peptide (i.e., peptide A) seen only in the A and AB profiles and (2) another peptide (i.e., peptide B) seen only in the B and AB profiles. Sequencing revealed that peptide A had glutamine at amino acid position 191, whereas peptide B was generated by cleavage on the carboxy side of position 191, presumably because there was a basic (trypsin-specific) amino acid at that position. Working independently, our laboratory and one other laboratory have sequenced the coding region for paraoxonase from human liver cDNA libraries and have identified two polymorphic sites: Arg/Gln at position 191 and Leu/Met at position 54. Using PCR amplification and direct sequencing of nucleotides in both polymorphic regions with genomic DNA, we have estimated the allelic frequencies and have determined their concordance with the serum paraoxonase allozyme phenotypes in 27 unrelated adults and in 16 members of a three-generation pedigree. Among unrelated individuals, the Met/Leu polymorphism at position 54 did not correlate with the serum esterase phenotype. In contrast, the particular amino acid at position 191 correlated perfectly with serum phenotypes: A-type individuals had Gln at position 191, and B-type individuals had Arg at position 191; AB-type serum was found only with the heterozygous (Arg/Gln) combination. Pedigree analysis showed both polymorphisms to be inherited in the expected Mendelian manner and confirmed that only the 191 polymorphism showed concordance with the serum paraoxonase/arylesterase phenotypes.