Hitomi Yutaka, Mukai Hidefumi, Yoshimura Hideaki, Tanaka Tsunehiro, Funabiki Takuzo
Department of Molecular Engineering, Kyoto University, Kyoto Daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
Bioorg Med Chem Lett. 2006 Jan 15;16(2):248-51. doi: 10.1016/j.bmcl.2005.10.016. Epub 2005 Oct 24.
To expand the repertoire of artificial enzymes that are constructed by replacing the natural prosthetic group of hemoproteins with non-natural cofactors, we examined incorporation of a non-porphyrinic ligand (1) into the heme-pocket of apomyoglobin in a non-covalent fashion. Ligand 1 is a highly conjugated 1,10-phenanthroline derivative, which shares some structural features with protoporphyrin IX; for example, molecular size and arrangement of hydrophobic and anionic parts. Addition of apomyoglobin to a solution of 1 induces clear changes in the absorption spectrum of 1, suggesting one-to-one incorporation of 1 into the heme cavity of apomyoglobin with an affinity of 6.3 x 10(6)M(-1). We found that the hydrolytic activity of apomyoglobin toward p-nitrophenyl hexanoate was greatly suppressed because of the incorporation of 1 into the heme-pocket.
为了拓展通过用非天然辅因子取代血红蛋白的天然辅基构建的人工酶的种类，我们研究了以非共价方式将一种非卟啉配体（1）掺入脱辅基肌红蛋白的血红素口袋中。配体1是一种高度共轭的1,10 - 菲咯啉衍生物，它与原卟啉IX具有一些结构特征；例如，分子大小以及疏水和阴离子部分的排列。将脱辅基肌红蛋白添加到1的溶液中会导致1的吸收光谱发生明显变化，这表明1以6.3×10⁶M⁻¹的亲和力一对一地掺入脱辅基肌红蛋白的血红素腔中。我们发现，由于1掺入血红素口袋，脱辅基肌红蛋白对对硝基苯基己酸酯的水解活性受到极大抑制。
