試験管内胆汁色素生成過程に関する研究 第1編 Hemin dimethyl esterからの胆汁色素生成過程について

Spectrochemical observations were chiefly attempted on the formation process of verdohemochrome from protohemin dimethyl ester by O(2) in the presence of ascorbic acid. And the results were as follows. 1. Verdohemochrome was obtained from pyridine hemin dimethyl ester by the action of ascorbic acid and O(2). And the process of this reaction was spectrophotometrically similar to that of hemin. 2. The reaction construction was same to that of hemin and the compound with the absorption maximum at 630mμ. was found in the course of this reaction, as a intermediate product. This product was purely obtained from pyridine hemin dimethyl ester by the action of H(2)O(2) in the presence of ascorbic acid, and it was transformed into verdohemochrome by O(2). 3. It was supposed that the compound with the absorption maximum at 630mμ. and verdohemochrome were dimethyl ester. Biliverdin could be extracted from the latter by HCl and it was difficult to conclude if it was dimethyl ester, but it was thought that some part of it was probably ester. The absorption curves of these reaction products were nearly same to that obtained from hemin. 4. The necessary concentration of ascorbic acid for the formation of verdohemochrome in 60% pyridine water was 9.4 Mol. to 1 Mol. of hemin dimethyl ester, and it was equivalent to 3/4 on the occation of hemin. It was thought that the difference was caused by the reactivity. And the necessary concentration of ascorbic acid decreased with increasing pyridine concentration. 5. The most appropriate concentration of ascorbic acid was the smallest amount described the above, on the view point of reaction velocity and verdohemochrome yield, and they decreased with the higher concentration of ascorbic acid than the above. However, the formation velocity of the compound with the absorption maximum at 630mμ. was increased with increasing the ascorbic acid concentration. 6. It was supposed that the catalytic action of the compound with the absorption maximum at 630mμ. and verdohemochrome was remarkably reinforced in the higher concentration of pyridine and it was thought that the secondary reaction by the excessive concentration of ascorbic acid was caused by the above action. The secondary reaction velocity of them was 1/2 of that obtained from hemin. 7. The abnormal reaction of the compound with the absorption maximum at 630mμ. was observed as the absorption band around 610mμ. The process of the further oxidation of verdohemochrome by ascorbic acid was, spectrophotometrically, quite similar to the oxidation of it by H(2)O(2), and both of them were oxidized to yellow substances. Positive pentdyopent reaction was observed in this process. 8. Since the above results, the reactivity of hemin was fairly declined by the esterification of carboxylic acid groups in the side chains, but it was recognized that the formation process of verdohemochrome was not essentially effected by the above esterification.