Elucidation of Reaction Mechanism of Abnormal Heme Metabolism by Synthetic Methods

通过合成方法阐明血红素代谢异常的反应机制

• 批准号: 12450368
• 负责人: OGOSHI Hisanobu
• 金额: $ 9.54万
• 依托单位: Fukui National College of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450368/
• 关键词: Protein Reconstitution; Heme Protein; N-Alkylsubstituted Porphyrin; Myoglobin; Heme Abnormal Metabolism; Normal; Reverse; Heme Pocket; NMR

Cobalt(II)complexes of N_A-ethyl and N_B-ethylmesoporphyrin dimethylester(the isomers with ethyl group on the A ring and B rings) have been prepared to elucidate the reaction mechanism of abnormal heme metabolism. The reconstituted myoglobins with the cobalt(II) complexes of N-ethylmesoporphyrin have been characterized by 1^H-NMR measurements.The reconstitution of apomyoglobin with 1.6 equivalent of Co(II)complexes of N_A-and N_B-ethylmesoporphyrin affordd stable myoglobins ((N_A-C_2H_5Meso)Co(II) and (N_B-C_2H_5Meso)Co(II)-Mb. The 1^H-NMR spectrum showed three signals at -34.75 ppm, -36.63 ppm and -48.61 ppm assigned to the methyl group of N-ethyl group, respectively.The chemical shifts of these signals were agreement with those of myoglobins reconstituted with (N_A-C_2H_5 Meso Co(II) and (N_B-C_2H_5Meso)Co(II), individually. The N-alkylmesoporphyrin coordinates with myoglobin in normal or reverse orientation because the heme pocket of yoglobin recognizes the sequence of side chains o … More f N-alkylmesoporphyrin. The signal at -34.75, -36.63 and -48.61ppm is assigned to the NA-CzHs of reverse orientation, N_A-C_2H_5 of normal orientation and N_B-C_2H_5 of reverse orientation, respectively. It seems that the steric repulsion of Na-ethyl group with isopropyl group of Val 68 in myoglobin is larger than that of N_A-ethyl group is responsible for the relative abundance of N_A-and N_B-ehyl group of reverse orientation(1 : 0.4). In addition, it seems that the relative abundance of N_A-ethyl group of reverse rientation and N_B-ethyl group of normal orientation (1 : 2) is dependent on the assumption that the N-ethylmesoporphyrin of normal orientation is referentially reconstituted with myoglobin because the heme pocket of myoglobin recognize the sequence of side chains of N-alkylmesoporphyrin.It can be seen from these results that the apomyoglobin recognizes a pair of enantiomers of N-alkylmesoporphyrin by the asymmetric heme pocket, and that the steric repulsion of N-ethyl group with Val 68 play an important role in the asymmetric recognition. It seems reasonable to assume that the relative abundance of the regioisomers of N-alkylmesoporphyrin reconstituted with myoglobin is tendency to migrate to pyrolle nitrogen atom of alkyl group. Less

制备了n_a -乙基和n_b -乙基介卟啉二甲基酯（A环和B环上有乙基的异构体）的钴（II）配合物，以阐明血红素代谢异常的反应机理。以n -乙基间卟啉钴（II）配合物重组的肌红蛋白通过1^H-NMR测量进行了表征。用1.6当量的n_a -和n_b -乙基中卟啉Co（II）配合物重构无肌红蛋白，得到稳定的肌红蛋白(（N_A-C_2H_5Meso)Co（II）和（N_B-C_2H_5Meso）Co(II)-Mb）。1^H-NMR谱在-34.75 ppm、-36.63 ppm和-48.61 ppm分别显示了n -乙基甲基的3个信号。这些信号的化学位移与分别由(N_A-C_2H_5 Meso Co（II）和（N_B-C_2H_5Meso）Co（II）重建的肌红蛋白的化学位移一致。n -烷基介卟啉与肌红蛋白的正位或反位是由于肌红蛋白的血红素袋能够识别肌红蛋白侧链的序列。-34.75、-36.63和-48.61ppm的信号分别分配给反向方向的na - chz、正方向的N_A-C_2H_5和反向方向的N_B-C_2H_5。肌红蛋白中na -乙基与Val - 68异丙基的空间斥力大于n_a -乙基，这可能是导致n_a和n_b -乙基相对丰度相反的原因（1:1 .4）。此外，由于肌红蛋白的血红素袋能够识别n -烷基介卟啉侧链的序列，因此反取向的n_a -乙基和正取向的n_b -乙基的相对丰富度（1:2）似乎取决于正取向的n -乙基介卟啉与肌红蛋白的参照重构。从这些结果可以看出，无肌红蛋白通过不对称血红素口袋识别n -烷基介卟啉的一对对映体，并且n -乙基与Val 68的空间排斥力在不对称识别中起重要作用。肌红蛋白重构的n -烷基间卟啉区域异构体的相对丰度倾向于向烃基的鹿蹄草氮原子迁移。少