Effect of Cytochrome P450 2C19 and 2C9 Amino Acid Residues 72 and 241 on Metabolism of Tricyclic Antidepressant Drugs
Effect of Cytochrome P450 2C19 and 2C9 Amino Acid Residues 72 and 241 on Metabolism of Tricyclic Antidepressant Drugs
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DOI：
10.1248/cpb.c13-00800
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发表时间：
2014-02-01
影响因子：
1.7
通讯作者：
Uno, Tadayuki
中科院分区：
文献类型：
--
作者：
Attia, Tamer Zekry;Yamashita, Taku;Uno, Tadayuki
虽然细胞色素P450 2C 9（CYP 2C 9）和2C 19（CYP 2C 19）具有91%的氨基酸同一性，但它们具有不同的底物特异性。以前的研究表明，几个氨基酸残基可能参与底物特异性。在这项研究中，我们专注于两个氨基酸残基72和241的作用。这些位置的氨基酸在CYP 2C 9和2C 19中具有相反的电荷;前者在两个位置（Lys 72和Lys 241）具有赖氨酸，后者具有谷氨酸（Glu 72和Glu 241）。产生了CYP 2C 19和2C 9的相互突变体，并使用三种三环类抗抑郁药（TCA）药物：阿米替林，丙咪嗪和dothiepin检查了它们的代谢活性和光谱特性。尽管CYP 2C 19野生型（WT）对所有三种药物都具有高代谢活性，但E72 K突变使酶活性降低了29- 37%，而结合亲和力降低了2.5- 20倍。另一方面，CYP 2C 9 WT的低活性和低亲和力通过K72 E突变显著恢复。代谢活性和结合亲和力受CYP 2C 19 E241 K和CYP 2C 9 K241 E突变的影响极小。我们还可以显示代谢活性和结合亲和力之间的线性相关性，因此我们得出结论，氨基酸残基72通过限制CYP 2C 19和CYP 2C 9的结合亲和力在TCA药物代谢中起关键作用。
Although cytochromes P450 2C9 (CYP2C9) and 2C19 (CYP2C19) have 91% amino acid identity, they have different substrate specificities. Previous studies have suggested that several amino acid residues may be involved in substrate specificity. In this study, we focused on the roles of two amino acids, residues 72 and 241. The amino acids in these positions have opposite charges in CYP2C9 and 2C19; the former has lysines in both positions (Lys72 and Lys241), and the latter has glutamic acids (Glu72 and Glu241). Reciprocal mutants for both CYP2C19 and 2C9 were produced, and their metabolic activities and spectroscopic properties were examined using three tricyclic antidepressant (TCA) drugs: amitriptyline, imipramine, and dothiepin. Although CYP2C19 wild-type (WT) had a high metabolic activity for all three drugs, the E72K mutation decreased enzymatic activity by 29-37%, while binding affinities were diminished 2.5- to 20-fold. On the other hand, low activity and low affinity of CYP2C9 WT were recovered notably by K72E mutation. The metabolic activities and binding affinities were minimally affected by CYP2C19 E241K and CYP2C9 K241E mutations. We could also show linear correlations between metabolic activities and binding affinities, and hence we conclude that amino acid residue 72 plays a key role in TCA drug metabolism by limiting the binding affinities of CYP2C19 and CYP2C9.