DNA POLYMORPHIC FORMS OF HUMAN SERUM CHOLINESTERASE

人血清胆碱酯酶（即丁酰胆碱酯酶，BChE）是 药理学的兴趣，因为其缺乏（或高水平）， 这种酶的几种变体形式的活性或改变的亲和力 引起对肌肉松弛药物的过度反应（或抵抗）， 琥珀胆碱 我们的实验室已经研究BChE超过25年。 博士洛克里奇确定了纯化的人源性氨基酸的完整序列。 血清BChE，我们从人脑cDNA文库中克隆了该基因， 对整个编码区进行测序，并使用基因组DNA来确定 与4个外显子相邻的内含子区域的大小和序列。 我们发现 最常见的BChE变体的结构基础;非典型，或 地布卡因耐药变异体，是核苷酸碱基209处的点突变 (GAT产生GGT）。 这将氨基酸70从Asp变为Gly。 的 到目前为止，在每一个接受测试的人身上都发现了相同的突变。 非典型BChE。 从那时起，我们使用PCR扩增来制备基因组DNA， 详细的序列分析，并已确定，到目前为止，结构 这是人类BCHE的另外22种天然突变的基础。 这些包括 酶的质的变化，如耐氟性， 三分之一（K）、三分之二（J）、90%（H）和 基本上没有酶活性（沉默）。 沉默组包括 点突变、移码突变、不稳定酶的产生，以及 肝脏不释放到血液中的酶。 大量 现在可以使用DNA分析诊断的变异要求， 我们使用DNA结构基础对BCHE基因型进行分类， 未来 我们正在开发新的筛选方法， 在抽样人群中调查这些变异的努力 代表不同的种族群体和不同的地理区域， 了解更多关于这些变异等位基因的分布。 人体三维结构研究的新进展 BChE使其能够可视化确切的位置并预测 不同氨基酸残基的重要性。 我们可以识别那些钥匙 组成酯酶活性中心的组分。 这一系列 天然BChE变体在未来的研究中应该非常有用， 酶结构中的特定修饰可以改变底物 特异性，（特别是与其他药物，如mivacurium）， 对抑制剂的反应，以及这些结构修饰如何影响 酯酶动力学。 这些研究的分子结构和 人类BChE的催化功能将提高我们对这些的理解。 该模型药物遗传学条件的分子水平事件。

Human serum cholinesterase, (i.e. butyrylcholinesterase, BChE) is of pharmacological interest because deficiencies (or high levels) of its activity or altered affinities in several variant forms of this enzyme cause an exaggerated response (or resistance) to the muscle-relaxant drug, succinylcholine. Our laboratory has been studying BChE for over 25 years. Dr. Lockridge determined the complete amino acid sequence of purified human serum BChE, and we cloned the gene from a human brain cDNA library, sequenced the entire coding region, and used genomic DNA to determined the size and sequence of the intron regions adjacent to the 4 exons. We found the structural basis of the most common BChE variant; the atypical, or dibucaine-resistant variant, to be a point mutation at nucleotide base 209 (GAT yields GGT). This changes amino acid 70 from Asp yields Gly. The identical mutation has been found, so far, in every person tested with atypical BChE. Since then, we have used PCR amplification to prepare genomic DNA for detailed sequence analyses, and have identified, to date, the structural basis for an additional 22 natural mutations of human BCHE. These include both qualitative alterations in the enzyme, such as fluoride-resistance, an quantitative reductions of one-third (K), two-thirds (J), 90% (H), and essentially no enzymatic activity (silent). The silent group includes point mutations, frame shift mutations, production of unstable enzymes, and enzymes that are not released from liver into the blood. The large number of variants that can now be diagnosed using DNA analyses has required that we use of a DNA structural basis for classifying BCHE genotypes in the future. We are developing new screening methods that should simplify efforts in making surveys for any of these variants in sample populations representing different ethnic groups, and different geographic areas to learn more about the distribution of these variant alleles. Recent advances in our knowledge about the 3-dimensional structure of human BChE make it possible to visualize the exact location and predict the importance of the different amino acid residues. We can identify those key components making up the active center of the esterase. This series of natural BChE variants should be very useful in future studies on how particular modifications in the enzymatic structure can alter the substrate specificity, (particularly with other drugs, such as mivacurium), the response to inhibitors, and how these structural modifications affect the kinetics of the esterase. These studies of the molecular structure and catalytic function of human BChE will improve our understanding of these events at a molecular level for this model pharmacogenetic condition.