An expressional system of human cytochrome P-450 CYP1A1 gene transcription

目的：在人ＨｅｐＧ２细胞系上，建立人细胞色素Ｐ４５０ＣＹＰ１Ａ１（ＣＹＰ１Ａ１）基因转录的表达系统．方法：瞬时转染含人ＣＹＰ１Ａ１启动子的质粒（ｐＭＣ６３Ｋ）、ＥＬＩＳＡ法测定报道基因氯霉素乙酰转移酶（ＣＡＴ）的含量和酶学测定ＣＹＰ１Ａ１活性．结果：β萘黄酮２．５μｍｏｌ·Ｌ－１明显增强ＣＡＴ表达和ＣＹＰ１Ａ１活性（Ｐ＜０．０１）；在２．５－１０μｍｏｌ·Ｌ－１范围内，ＣＡＴ表达随浓度增高而不断增强，而ＣＹＰ１Ａ１活性则接近最高水平；１０μｍｏｌ·Ｌ－１时它们的作用强度分别为对照组的９４．３和２．８倍．用这种方法对八种含不同侧链的芥子油苷进行检测的结果表明，芸苔苷的水解产物（而非吲哚３原醇）诱导ＣＹＰ１Ａ１基因表达．结论：ＣＹＰ１Ａ１基因转录表达系统具有较高的可靠性和灵敏度     

与细胞色素P_(450)1A2相关的药物相互作用

细胞色素Ｐ４５０(ＣＹＰ４５０)是一个由结构和功能相关的基因超家族编码的同工酶所组成的超家族酶系。它参与许多内源性和外源性物质的生物转化 ,在调节机体与外界环境的相互作用以及保持机体内环境的稳态方面起着十分重要的作用。ＣＹＰ１Ａ２［１］是Ｐ４５０ 家族中成员之一。在肝脏中 ,其含量占Ｐ４５０ 蛋白总量的１３ % ,仅次于ＣＹＰ３Ａ和ＣＹＰ２Ｃ居第３位 ,且在不同的个体 ,ＣＹＰ１Ａ２在肝脏内的含量及其活性的差异可高达６０倍以上。现已发现 ,许多药物经ＣＹＰ１Ａ２催化代谢。芳胺、杂环胺及一些含卤烃化物均是ＣＹＰ１Ａ…     

CYP1A2在体内氯氮平去甲基代谢中的作用

通过检测咖啡国及其代谢产物,探讨细胞色素Ｐ４５０酶的亚型１Ａ２（ＣＹＰ１Ａ２）在体内氯氮平去甲基代谢的作用。９例男性健康志愿者口服单剂咖啡因１５０ｍｇ,５ｈ时采用取血样的尿样,咖啡因代谢产物与咖啡因的比值反映ＣＹＰ１Ａ２活性。两天后单剂氯氮平１０ｍｇ,收集０～２４ｈ尿和药代动力学设计的血样。０～２４ｈ尿中氯氮平剩余量占给药剂量的百分率（ＣＬＺ％ｄｏｓｅ）以及氯氮平０～２４药时曲线下面积（ＡＵＣ０→     

细胞色素P450同工酶在外源物代谢中的作用

细胞色素Ｐ４５０酶系（ＣＹＰ）中的Ｐ４５０Ⅰ￣Ｐ４５０Ⅳ家族是代谢外来化合物的主要酶系。环境致癌主要是ＣＹＰ１Ａ的底物，ＣＹＰ２Ｄ６的突出特征是它的遗传多态性，而ＣＹＰ２Ｅ１主要参与乙醇等小分子化合物的代谢，ＣＹＰ３Ａ则是参与大多数临床口服药物代谢的主要同工酶。本文综述了细胞色素Ｐ４５０铎外源性化合物代谢转换及调控研究，对ＣＹＰ１Ａ、ＣＹＰ２Ｅ的诱导机制及ＣＹＰ３Ａ的主要抑制机制也作了叙述。     

ASA法测定细胞色素P4502D6酶缺陷等位基因CYP2D6E

目的：建立细胞色素Ｐ４５０ ２Ｄ６（ＣＹＰ２Ｄ６）第３０２３位Ａ→Ｃ突变成ＣＹＰ２Ｄ６酶活性缺陷的等位基因ＣＹＰ２Ｄ６Ｅ的测定方法。方法：利用等位基因特异扩增法（ＡＳＡ）为基本原理,设计两对引物分别扩增野生型等位基因和突变型等位基因。结果：经３９６例测定,发现２例ＣＹＰ２Ｄ６Ｅ与ＣＹＰ２Ｄ６Ｂ的异突变型纯合子,其表现型均为慢代谢者。     

与细胞色素P4501A2相关的药物相互作用

细胞色素Ｐ４５０(ＣＹＰ４５０)是一个由结构和功能相关的基因超家族编码的同工酶所组成的超家族酶系。它参与许多内源性和外源性物质的生物转化 ,在调节机体与外界环境的相互作用以及保持机体内环境的稳态方面起着十分重要的作用。ＣＹＰ１Ａ２［１］是Ｐ４５０ 家族中成员之     

肝病患者药物代谢酶细胞色素P450酶1A2,多态性N—乙酰化 …

目的以咖啡因为代谢探针，研究肝患者咖啡因代物比值（ｃａｆｆｅｉｎｅ ｍｅｔａｂｏｌｉｔｅ ｒａｔｉｏｓ，ＣＭＲｓ）的变化，探讨ＣＭＲｓ作为药工谢酶细胞色素Ｐ４５０酶１Ａ２（ＣＹＰ１Ａ２）、多态性Ｎ－乙酰基转移酶（ＮＡＴ２）、黄嘌呤氧化化酶（ＸＯ）的活性指标，用于调整某些药物用药方案的可行性。方法：选择健康受者３０例，慢性肝病受试者３０例。采用高效液相色谱（ＨＰＬＣ）法测定受试者尿液３０例，慢性肝病     

咖啡因试验与氯氮平体内代谢的相关性

通过检测尿中咖啡因（Ｃａｆ）及其代谢产物,探讨细胞色素Ｐ４５０ １Ａ２（ＣＹＰ１Ａ２）与体内氯氮平（ＣＬＺ）去甲基代谢物的关系。方法单剂ｐｏ Ｃａｆ１５０ｍｇ,ｈ５末采取尿样,以Ｃａｆ代谢产物和Ｃａｆ的比值「（１７Ｘ＋１７Ｕ）／１３７Ｘ」反映ＣＹＰ１Ａ２活性。２ｄ后单剂ｐｏＣＬＺ１０ｍｇ,收集０－２４ｈ尿样。０－２４ｈ悄中ＣＬＺ剩余量占给药剂量的分率（ＣＬＺ％）反映ＣＬＺ清除;０－２４ｈ尿中去甲     

肝细胞色素P_(450)与药物代谢的研究进展

外源性化合物特别是药物进入体内后 ,很多都经过肝脏代谢 ,而肝药酶ＣＹＰ４５０ 是肝代谢药物的主要酶系。ＣＹＰ４５０ 同工酶能代谢药物使其失活 ,也能使某些无活性的物质转化成活性物质而产生药理作用或毒性。肝脏中ＣＹＰ４５０ 的不同类型及不同含量将直接影响药物的代谢转化、药物间相互作用等 ;同时 ,外源性化合物也能影响ＣＹＰ４５０ 在肝脏的表达 ,从而诱导或抑制其活性。了解ＣＹＰ４５０ 的特性 ,调控ＣＹＰ４５０ 的表达水平有助于临床合理用药及预防疾病 ,也一直是该领域的研究热点之一。１肝细胞色素Ｐ４５０ 同工酶迄今为…     

吡喹酮在诱导和未诱导大鼠肝微粒体内的羟化代谢概貌及其羟化物的质谱鉴定

用细胞色素Ｐ４５０（Ｐ４５０）特异诱导剂研究参与吡喹酮（ＰＱＴ）代谢的Ｐ４５０同工酶，在未诱导肝微粒体内，ＰＱＴ代谢仅生成其Ｄ环单羟化物．在β－萘黄酮诱导肝微粒体内，ＰＱＴ代谢后也生成其Ｄ环单羟化物．ＰＱＴ在苯巴比妥诱导的肝微粒体内代谢生成Ｄ环，Ｂ环和Ａ环三个单羟化物．在地塞米松和红霉素诱导的肝微粒体内，ＰＱＴ代谢生成七个代谢产物．结果表明参与ＰＱＴ分子羟化的Ｐ４５０同工酶至少包括ＣＹＰ１Ａ，ＣＹＰ２Ｂ和ＣＹＰ３Ａ亚家族，每个亚家族代谢ＰＱＴ的概貌各不相同，ＣＹＰ３Ａ优先羟化Ａ环，ＣＹＰ２Ｂ优先羟化Ｄ环和Ｂ环，ＣＹＰ１Ａ则几乎仅羟化Ｄ环．     

Molecular modelling of CYP1 family enzymes CYP1A1, CYP1A2, CYP1A6 and CYP1B1 based on sequence homology with CYP102

Molecular modelling of a number of CYP1 family enzymes from rat, plaice and human is described based on amino acid sequence homology with the haemoprotein domain of CYP102, a unique bacterial P450 of known structure. The interaction of various substrates and inhibitors within the putative active sites of rat CYP1A1, human CYP1A2, a fish CYP1 enzyme CYP1A6 (from plaice) and human CYP1B1, is shown to be consistent with P450-mediated oxidation in each example or, in the case of inhibitors, mechanism of inhibition. It is reported that relatively small changes between the enzymes' active site regions assist in the rationalization of CYP1 enzyme preferences for particular substrate types, and a template of superimposed CYP1A2 substrates is shown to fit the putative active site of the human CYP1A2 enzyme.     

测定咖啡因代谢物评价 N-乙酰转移酶、CYP1A2和黄嘌呤氧化酶活性

目的是对中国人N-乙酰化酶(NAT2)、CYP1A2酶和黄嘌呤氧化酶(XO)的活性进行分析。120名健康志愿者饮用3杯咖啡后于4～5h留尿,用HPLC方法测定尿中5种咖啡因主要代谢物浓度,即5-乙酰胺基-6-甲酰胺基-3-甲基尿嘧啶(AFMU)、1-甲基黄嘌呤(1X)、1-甲基尿酸(1U)、1,7-二甲基尿酸(17X)、1,7-二甲基黄嘌呤(17U)。其中N-乙酰化酶活性用AFMU/1X或AFMU/(AFMU+1X+1U)表示;CYP1A2酶活性指标采用(AFMU+1X+1U)/17X或AFMU+1X+1U)/17U;XO酶活性指标采用1U/1X或1U/(1X+1U)。结果表明,N-乙酰化酶活性呈两态分布,慢代谢者占16.7%,CYP1A2和XO酶活性呈对数正态分布,其代谢比值与国外文献报道一致。提示通过测定咖啡因代谢物比值,可以进行NAT2酶、CYP1A2酶和黄嘌呤氧化酶活性分析。     

Differential inhibition of human CYP1A1 and CYP1A2 by quinidine and quinine

1. The inhibition of recombinant CYP1A1 and CYP1A2 activity by quinidine and quinine was evluated using ethoxyresorufin O -deethylation, phenacetin O -deethylation and propranolol desisopropylation as probe catalytic pathways. 2. With substrate concentrations near the K m of catalysis, both quinidine and quinine potently inhibited CYP1A1 activity with [I] 0.5 ~ 1-3 μM, whereas in contrast, there was little inhibition of CYP1A2 activity. The Lineweaver-Burk plots with varying inhibitor concentrations suggested that inhibition by quinidine and quinine was competitive. 3. There was only trace metabolism of quinidine by recombinant CYP1A1, whereas rat liver microsomes as a control showed extensive consumption of quinidine and metabolite production. 4. This work suggests that quinidine is a non-classical inhibitor of CYP1A1 and that it is not as highly specific at inhibiting CYP2D6 as previously thought.     

Preferential induction of CYP1A1 and CYP1B1 in CCSP-positive cells.

Both benzo[a]pyrene (BaP) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are potent ligands of aryl hydrocarbon receptors (AhR). Although animal studies indicate that both compounds induce pathological changes in the peripheral lung, the specific cell type involved remains unclear. Clara cells, expressing Clara cell specific protein (CCSP) and abundant in cytochrome P450, are nonciliated bronchiolar epithelial cells in the peripheral lung. Here we explore the hypothesis that CCSP-positive Clara cells are highly responsive to AhR ligands and are the primary cell type involved in BaP- and TCDD-induced toxicities. The responsiveness to AhR ligands was evaluated by measuring the respective mRNA and protein levels of cytochrome P450 1A1 (CYP1A1) and 1B1 (CYP1B1) using real-time RT-PCR and immunocytochemistry assays. Two in vitro models were used: primary cultures of human small airway epithelial (SAE) cells and rat lung slice cultures. In the presence of calcium, human SAE cells differentiated into CCSP-positive cells. BaP- and TCDD-induced mRNA and protein levels of CYP1A1 and CYP1B1 levels were significantly elevated in CCSP-positive cell cultures. Similarly, AhR mRNA and protein levels were increased in CCSP-positive cell cultures, as determined by real-time RT-PCR and Western blot analysis. When rat lung slice cultures were treated with BaP or TCDD for 24 h, CYP1A1 and CYP1B1 proteins were strongly induced in Clara cells. These results indicate that, in the peripheral lung of both rats and humans, CCSP-positive cells (Clara cells) may be more sensitive to AhR ligands than other cell types.     

Differential inhibition of human CYP1A1 and CYP1A2 by quinidine and quinine.

1. The inhibition of recombinant CYP1A1 and CYP1A2 activity by quinidine and quinine was evluated using ethoxyresorutin O-deethylation, phenacetin O-deethylation and propranolol desisopropylation as probe catalytic pathways. 2. With substrate concentrations near the Km of catalysis, both quinidine and quinine potently inhibited CYP1A1 activity with [I](0.5) approximately 1-3 microM, whereas in contrast, there was little inhibition of CYP1A2 activity. The Lineweaver-Burk plots with varying inhibitor concentrations suggested that inhibition by quinidine and quinine was competitive. 3. There was only trace metabolism of quinidine by recombinant CYP1A1, whereas rat liver microsomes as a control showed extensive consumption of quinidine and metabolite production. 4. This work suggests that quinidine is a non-classical inhibitor of CYP1A1 and that it is not as highly specific at inhibiting CYP2D6 as previously thought.