Open AccessBiotin-Bound CO 2 and the Mechanism of Enzymatic Carboxylation Reactions
Author(s) -
Thomas C. Bruice,
A. F. Hegarty
Publication year - 1970
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.65.4.805
Subject(s) - carboxylation , biotin , chemistry , intramolecular force , enzyme , oxygen , biochemistry , stereochemistry , organic chemistry , catalysis
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 theO -acylisourea formed by this route (relative to anN -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.