High conformational stability of cytochrome P-450 1A2. Evidence from UV absorption spectra
High conformational stability of cytochrome P-450 1A2. Evidence from UV absorption spectra
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DOI：
10.1135/cccc19980441
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发表时间：
1998-03-01
影响因子：
--
通讯作者：
Anzenbacherova, E
中科院分区：
文献类型：
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作者：
Anzenbacher, P;Bec, N;Anzenbacherova, E
利用260 ~ 310 nm吸收光谱的四阶导数监测细胞色素P-450 1A 2中酪氨酸和色氨酸侧链暴露于溶剂的变化。滴定的酶与特定的抑制剂，α-萘甲酮（2-phenylazo[h]chromen-4-one）的抑制剂浓度为30 μ M导致小，但明显的变化，衍生光谱（减少在最大振幅，下移的光谱最大值在约293 nm）对应于曝光的Dahans对溶剂。进一步添加抑制剂导致这些芳族侧链的暴露减少。在这项工作中也观察到其他细胞色素P-450（2B 4和11 A1）的类似行为。吸收光谱的四阶导数也用于检查在α-萘甲酮的存在和不存在下的酶的稳定性，以增加的压力（高达400 MPa）和温度（高达35 ℃）作为每管因子。结果表明，细胞色素P-450 1A 2具有稳定的构象，因为观察到的所有构象变化（光谱）完全可逆。
The fourth derivative of absorption spectra between 260 and 310 nm were used for monitoring the changes in exposure of tyrosine and tryptophan side chains in cytochrome P-450 1A2 to solvent. Titration of the enzyme with a specific inhibitor, alpha-naphthoflavone (2-phenylazo[h]chromen-4-one) to inhibitor concentration of 30 mu M resulted in small but pronounced changes in derivative spectra (decrease in the maximum amplitude, downshift of the spectral maximum at about 293 nm) corresponding to the exposure of tryptophans towards the solvent. Further addition of the inhibitor led to a decrease of the exposure of these aromatic side-chains. Similar behaviour was also observed in this work for other cytochromes P-450 (2B4 and 11A1). The fourth derivative of absorption spectra was also used to examine the stability of the enzyme both in the presence and absence of alpha-naphthoflavone, with increasing pressure (up to 400 MPa) and temperature (up to 35 degrees C) as pertubing factors. The results show that cytochrome P-450 1A2 has a stable conformation as all the conformational changes observed were (spectrally) fully reversible.