期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1970
卷号：65
期号：4
页码：805-809
DOI：10.1073/pnas.65.4.805
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Considerations are provided which show that the carboxylation site (oxygen or nitrogen) of biotin is most likely unknown. Kinetic studies of intramolecular reactions of the ureido function at acyl carbon demonstrate that ureido oxygen attack is the preferred mode when the acyl group is activated. Transfer from the O-acylisourea formed by this route (relative to an N-acylurea) is also favorable. These model studies are related to the carboxylation and CO2 transfer steps of biotin-mediated reactions, and a mechanism consistent with these results is postulated.
