Metabolism of leukotrienes.
Metabolism of leukotrienes.
复制标题
白三烯的代谢。
DOI：
10.1007/bf00225922
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发表时间：
1985
影响因子：
4.3
通讯作者：
Bernström,K
中科院分区：
文献类型：
--
作者：
Hammarström,S;Orning,L;Bernström,K
白三烯b4的体外代谢是由ω-羟基化引发的。这个反应之后ω-羟基氧化为羧基。白三烯b4在体内发生广泛的β氧化，主要的排泄产物是水和二氧化碳。在体外进行的实验表明，含白三烯的谷胱甘肽代谢的主要途径涉及三肽取代基的修饰。代谢改变是由酶消除n端y-谷氨酰基残基引起的，由γ-谷氨酰基转移酶催化。这个反应之后是剩余肽键的水解，导致c端甘氨酸残基的消除。催化后一反应的酶是一种膜结合二肽酶，存在于肾脏和其他组织中。这些反应形成的产物白三烯E4已初步确定为静脉注射白三烯C4后男性尿液代谢物。在大鼠中，白三烯C44的两种主要粪便代谢特征为n -乙酰基白三烯E4和n -乙酰基11-转白三烯E4。这些化合物是在白三烯e4或11-trans白三烯e4和乙酰辅酶a之间的反应中形成的。这些反应是由存在于肝、肾和其他组织中的膜结合酶催化的。
Thein vitrometabolism of leukotriene B4is initiated by ω-hydroxylation. This reaction is followed by oxidation of the ω-hydroxyl group to a carboxyl group.In vivoextensive β-oxidation occurs and the main excreted products after administration of leukotriene B4are water and carbon dioxide.Experiments performedin vitroandin vivohave demonstrated that a major pathway of metabolism of the glutathione containing leukotrienes involves modifications of the tripeptide substituent. The metabolic alterations are initiated by enzymatic elimination of the N-terminal y-glutamyl residue, catalyzed by the enzyme γ-glutamyl transferase. This reaction is followed by hydrolysis of the remaining peptide bond resulting in elimination of the C-terminal glycine residue. The enzyme catalyzing the latter reaction is a membrane bound dipeptidase which occurs in kidney and other tissues. The product formed by these reactions, leukotriene E4, has been tentatively identified as a urinary metabolite in man following intravenous administration of leukotriene C4. In rats, the two major fecal metabolities of leukotriene C44 were characterized as being N-acetyl leukotriene E4 and N-acetyl 11-transleukotriene E4. These compounds are formed in reactions between leukotriene E4or 11-transleukotriene E4and acetyl coenzyme A. The reactions are catalyzed by a membrane bound enzyme present in liver, kidney and other tissues.