Drug Metabolizing Enzymes In Humans And Animal Models

成就：我们已经确定了人类中β-内酰胺酶家族的遗传多态性，这是某些药物和环境化学品的可变代谢以及人类对这些化学品的易感性改变的原因。通过重测序，我们在来自3个种族的72名个体中发现了21个SNP，其中包括两个编码改变的等位基因：CYP 2C 8 *2（Ile 269 Phe）和CYP 2C 8 *3（Arg 139 Lys和Lys 399 Arg）。基因检测显示，CYP 2C 8 *2见于非洲裔美国人，而CYP 2C 8 *3主要见于高加索人。利用重组cDNA表达系统，我们发现CYP 2C 8 *3在抗癌药物紫杉醇以及内源性化合物花生四烯酸的代谢中存在缺陷。CYP 2C 8在人心脏和血管中表达，因此具有额外的临床意义。CYP2C9。在CY 2C 9中发现了一种新的无效突变，该突变使抗惊厥药苯妥英的代谢降低了85%，这是一名对苯妥英表现出严重临床毒性的非裔美国患者。该个体为CYP 2C 9新缺失突变体纯合子。这是这种临床上重要的酶的无效多态性的第一个例子。人口研究表明，这种突变在非洲裔美国人中发现，但在高加索人中不存在或罕见。在CYP 3A 4中发现了新的多态性，CYP 3A 4代谢几乎一半的临床已知药物。两个氨基酸的变化影响催化活性对有机磷农药毒死蜱，和激素睾酮。这些氨基酸变化的影响正在细菌cDNA表达系统中解决。对72名个体的CYP 2C 9进行重新测序，发现了6个新的编码变化。这些后果正在研究使用定点诱变和cDNA表达系统。CYP 2C 19代谢抗溃疡药奥美拉唑、抗惊厥药美芬妥英、安定、某些巴比妥类药物，激活某些抗疟药，并使杀虫剂甲拌磷亚砜化。在CYP 2C 19中检测到9种新的多态性。它们的作用将在重组cDNA表达系统中得到解决。

ACCOMPLISHMENTS: We have identified genetic polymorphisms in the CYP family in humans which are responsible for the variable metabolism of certain drugs and environmental chemicals and altered susceptibility of humans to these chemicals. By resequencing efforts we have found 21SNPs in 72 individuals from 3 racial groups resequenced for human CYP2C8 including two alleles with coding changes : CYP2C8*2( Ile269Phe) and CYP2C8*3(Arg139Lys and Lys399Arg). Genetic tests showed CYP2C8*2 is found in African-Americans, and CYP2C8*3 primarily in Caucasians. Using recombinant cDNA expression systems, we found CYP2C8*3 is defective in the metabolism of the anticancer drug taxol as well as the endogenous compound arachidonic acid. CYP2C8 is expressed in human heart and blood vessels and is therefore of additional clinical interest. CYP2C9. A new null mutation was found in CY2C9 which decreased metabolism of the phenytoin by 85% in an African-American patient exhibiting severe clinical toxicity to the anticonvulsant phenytoin. The individual was homozygous for a new deletion mutant of CYP2C9. This is the first example of a null polymorphism in this clinically important enzyme. Population studies showed that the mutation was found in African-Americans but absent or rare in Caucasians. New polymorphisms have been discovered in CYP3A4 which metabolizes almost half of all clinically known drugs. Two amino acid changes affect catalytic activity toward the organophosphorus pesticide chlorpyrifos, and the hormone testosterone. The effects of these amino acid changes are being addressed in a bacterial cDNA expression system. Resequencing of CYP2C9 in 72 individuals has uncovered six new coding changes. The consequences of these are being studied using site-directed mutagenesis and cDNA expression systems. CYP2C19 metabolizes the antiulcer drug omeprazole, the anticonvulsant mephenytoin, valium, certain barbiturates, activates certain antimalarials, and sulfoxidizes the pesticide phorate. Nine new polymorphisms have been detected in CYP2C19. Their effects will be addressed in recombinant cDNA expression systems.