期刊名称：Journal of Nutritional Science and Vitaminology
印刷版ISSN：0301-4800
电子版ISSN：1881-7742
出版年度：1993
卷号：39
期号：2
页码：115-125
DOI：10.3177/jnsv.39.115
出版社：Center for Academic Publications Japan
摘要：Three analogs of adenosylcobalamin were synthesized and their coenzymic properties in the diol dehydrase reaction were studied. Neither adenosylcobinamide nor adenosylcobinamide phosphate was active as coenzyme and showed very low affinity for apoenzyme, irrespec-tive of the presence of nucleotide loop fragments, such as 5, 6-dimethyl-benzimidazole, α-D-ribazole, or α-D-ribazole-3'-phosphate. The coordina-tion of pyridine to the cobalt atom neither confers the coenzymic function upon adenosylcobinamide nor strengthens the inhibitory effect of cyano-aquacobinamide and methylcobinamide significantly. The analog of adenosylcobalamin in which the N-3 position of 5, 6-dimethylbenz-imidazole is methylated was also not active as coenzyme and showed very low affinity for apoenzyme. Since 3, 5, 6-trimethylbenzimidazole in this analog is no longer coordinated to the cobalt atom, these results show that at least a part of the nucleotide loop moiety coordinated to the cobalt atom of adenosylcobalamin is essential for tight binding to the apoenzyme and therefore for manifestation of coenzymic function.
