New york ( reuters health ) dec 19 - carriers of a polymorphism of the cytochrome p450 enzyme are at higher risk of miscarriage in the first trimester of pregnancy , karolinska university investigators report in the november issue of fertility and sterility 纽约（路透社健康版） 12月19日? ?卡罗琳斯卡大学的研究者在11月号的《生育与不育》上撰文指出，细胞色素p450酶多态性携带者妊娠早期流产的风险要大一些。
Toxicology : glutathione is a key substrate for the cytochrome p450 metabolic pathway , which is taxed daily , not only by a variety of prescription and non - prescription drugs , but also by a host of environmental toxins including heavy metals and many by - products of cigarette smoke and fuel exhaust 毒理学：谷胱甘肽是细胞色素p450代谢途径的关键基质，每天都被除了各种的处方和非处方药品外还有包括重金属、抽烟副产物及排气等许多的环境毒物所消耗。
Cytochrome p450 functions as the monooxygenase . p450s are involved in physiologically important processes including steroid metabolism , drug deactivation , procarcinogen activation , fatty acid metabolism , xenobiotic detoxification and wildly distributed in animal , plant and low eukaryotic organism 细胞色素p450具有加单氧酶的作用，并能参与机体解毒、甾体激素的合成、脂肪酸代谢等重要的生理反应，并广泛分布于动物、植物和低等真核生物中。
Among avian orders , the anseriformes ( screamers and waterfowls ) are a morphologically and biologically diverse group containing ca . 150 species distributed worldwide except antarctica . this paper will review the phylogeny of anseriformes firstly and then discuss the molecular phylogeny of anseriformes based on the genetic variation of mitochondrial 12s rrna gene and cytochrome b gene respectively 本文首先对雁形目鸟类的系统发生研究进行了综述，然后分别基于雁形目鸟类线粒体dna12srrna基因和细胞色素b基因全序列的遗传变异分析，探讨了雁形目鸟类分子系统发生。
Analysis of the sequence variation of cytochrome b gene indicated that there is no evidence of insertions or deletions , i . e . , they are all of identical length of 1143 bp in all the sequences of cytochrome b gene . further , the sequences can be fully translated into amino acid using chicken mitochondrial codon without nonsense mutations or intervening stop codons . the 1143 bp cytochrome b alignment contained 416 variable sites , of which 306 were parsimony informative sites with the strongest variable in third codon positions and less variable in first and second codon positions 细胞色素b基因序列变异分析表明： 1 ）雁形目鸟类细胞色素b基因全序列长度一致，无插入和缺失：对照鸡线粒体密码子系统全序列能全部翻译成氨基酸序列，无无义突变，全序列内部无终止密码子； 2 ）序列比对后1143加，含416个核着酸变异位点， 306个简约信息位点，其中处于密码子第三位的变异最大，第一位和第二位碱基的变异相对较小。
